I85PREP
⌘ K
OSSLT study materials
OSSLT study resources

OSSLT practice questions

One question at a time. Build your OSSLT understanding.

First 50 of 198 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Reading

Read this sentence: 'The school cafeteria will close early on Friday because the staff is attending a safety workshop.' What is the main reason the cafeteria is closing early?

  1. The building is being repaired.
  2. The cafeteria has run out of food.
  3. Friday is a school holiday.
  4. The staff is attending a workshop. Correct answer.

Explanation

The sentence states the cause directly with the word 'because': the staff is attending a safety workshop. A reader should connect the stated cause to the effect of closing early. No other reason is mentioned in the sentence.

Question 2Reading

Read this passage: 'Maya packed her bag the night before the hike. She checked the weather twice and laid out warm clothes. At dawn she was already at the trailhead.' Which word best describes Maya?

  1. Careless
  2. Reluctant
  3. Confused
  4. Prepared Correct answer.

Explanation

Maya's actions, such as packing early, checking the weather, and arriving at dawn, all show planning ahead. A reader combines these details to infer a character trait. The details consistently point to being prepared rather than any negative trait.

Question 3Reading

Which sentence is punctuated correctly?

  1. We need, eggs milk and bread.
  2. We need eggs milk and bread.
  3. We need eggs milk, and bread.
  4. We need eggs, milk, and bread. Correct answer.

Explanation

Items in a list of three or more are separated by commas, including before the final 'and' in standard school usage. The other sentences either omit needed commas or place them incorrectly. Correct listing punctuation keeps each item distinct for the reader.

Question 4Reading

A notice reads: 'Library books must be returned by the due date. A fine of 25 cents per day will be charged for late items.' According to the notice, what happens if a book is returned late?

  1. The due date is extended.
  2. The borrower loses library access.
  3. The book must be replaced.
  4. A daily fine is charged. Correct answer.

Explanation

The notice states a fine of 25 cents per day for late items, so the consequence is a daily charge. The reader must locate the sentence about late returns and match it to the question. No other consequence is described.

Question 5Reading

Read this sentence: 'The puppy bounded across the yard, chasing every leaf the wind tossed.' What does the word 'bounded' most nearly mean here?

  1. Barked
  2. Jumped Correct answer.
  3. Slept
  4. Hid

Explanation

Context clues such as 'across the yard' and 'chasing' show energetic movement. 'Bounded' means moved with leaps or springs. Substituting each option into the sentence confirms that only 'jumped' fits the action described.

Question 6Reading

Which of these is a complete sentence?

  1. After the long assembly.
  2. The students finished their projects. Correct answer.
  3. Because the bus was late.
  4. Running quickly down the street.

Explanation

A complete sentence needs a subject and a verb that express a full thought. 'The students finished their projects' has both. The other options are fragments that begin with a describing phrase or a connecting word and leave the thought unfinished.

Question 7Reading

Read this passage: 'The town planted trees along Main Street. Shoppers now stop to rest in the shade, and store owners report more visitors on hot days.' What is the main idea of the passage?

  1. Main Street is the busiest road.
  2. Store owners dislike hot weather.
  3. Trees are difficult to plant.
  4. Planting trees brought benefits to the town. Correct answer.

Explanation

The passage describes a change and then lists positive results, such as resting shoppers and more visitors. The main idea sums up those benefits. Supporting details about shade and visitors serve that central point rather than standing alone.

Question 8Reading

In the sentence 'The chef tasted the sauce and added more salt,' what is the verb?

  1. More
  2. Sauce
  3. Chef
  4. Tasted Correct answer.

Explanation

A verb expresses an action or state. In this sentence 'tasted' tells what the chef did. The other words are nouns or modifiers that do not express the action.

Question 9Reading

A student reads a poster: 'Bike to School Week begins Monday. Students who ride their bikes each day can enter a prize draw.' Which statement is supported by the poster?

  1. Riding daily makes a student eligible for a draw. Correct answer.
  2. The event lasts for one month.
  3. Students must own a new bike to enter.
  4. Only grade nine students may enter.

Explanation

The poster says students who ride each day can enter a prize draw, so daily riding is the stated condition. The reader should check each option against the exact wording. Options that add requirements not in the text are unsupported.

Question 10Reading

Read this paragraph: 'Many people think bats are blind. In fact, bats can see, but most rely on sound to navigate in the dark. They send out calls and listen for echoes that bounce off objects.' What does the paragraph suggest about bats?

  1. They cannot see at all.
  2. They use sound to find their way. Correct answer.
  3. They avoid flying at night.
  4. They are closely related to birds.

Explanation

The paragraph explains that bats send calls and listen for echoes to navigate, which is using sound. It also corrects the idea that bats are blind. The correct answer restates the paragraph's central explanation.

Question 11Reading

Which sentence uses the apostrophe correctly?

  1. The dogs bowl is empty.
  2. The dogs' bowl is empty for one dog.
  3. The dog's are barking.
  4. The dog's bowl is empty. Correct answer.

Explanation

An apostrophe before 's' shows possession by one dog, which matches 'bowl' belonging to a single dog. Plural possession would need the apostrophe after the 's'. Apostrophes also never form a simple plural verb.

Question 12Reading

Read these two sentences: 'The concert was scheduled for 7 p.m. A power outage delayed the start by an hour.' What time did the concert most likely begin?

  1. 8 p.m. Correct answer.
  2. 6 p.m.
  3. 9 p.m.
  4. 7 p.m.

Explanation

The start was scheduled for 7 p.m., and an hour-long delay moves the start to 8 p.m. The reader must combine the scheduled time with the length of the delay. Choosing the scheduled time ignores the delay.

Question 13Reading

A weather report says: 'Heavy rain is expected overnight, clearing by noon tomorrow.' A student plans a morning bike ride. What is the best advice based on the report?

  1. Cancel all outdoor plans for the week.
  2. Wait until the afternoon when the rain clears. Correct answer.
  3. Expect snow instead of rain.
  4. Ride early because rain will stop at dawn.

Explanation

The report says rain clears by noon, so an afternoon ride avoids the wet morning. Applying the forecast to the student's plan requires matching the clearing time to the activity. The other options misread the timing or the type of weather.

Question 14Reading

Read this sentence: 'Although the trail was steep, the hikers reached the summit before sunset.' Which relationship does the word 'although' show between the two parts?

  1. Sequence of time
  2. Contrast Correct answer.
  3. Addition
  4. Cause and effect

Explanation

'Although' signals that one idea contrasts with an expected result, here the difficulty of the trail versus the successful arrival. Recognizing signal words helps a reader follow the logic of a sentence. Cause, sequence, and addition each have different connecting words.

Question 15Reading

Which word best completes the sentence? 'The instructions were so ______ that everyone finished the task in minutes.'

  1. confusing
  2. noisy
  3. clear Correct answer.
  4. lengthy

Explanation

The result clause says everyone finished quickly, so the instructions must have been easy to follow. The blank needs a word that explains that quick success. The other options would produce results that contradict the sentence.

Question 16Reading

Read this passage: 'Some cities are replacing parking lots with small parks. These parks cool the air, absorb rainwater, and give residents a place to gather.' What is the author's main purpose?

  1. To list the costs of city parks
  2. To describe how to build a parking lot
  3. To argue that cars should be banned
  4. To explain benefits of turning lots into parks Correct answer.

Explanation

The passage presents a change and then lists several advantages, such as cooling air and absorbing rain. That pattern signals an explanatory purpose focused on benefits. It does not push a ban or discuss costs.

Question 17Reading

Choose the sentence that correctly combines these ideas: 'The library was closed. We studied at home.'

  1. The library was closed, but we studied at home because.
  2. The library was closed, so we studied at home. Correct answer.
  3. The library was closed we studied at home.
  4. The library was closed, or we studied at home.

Explanation

The library being closed is the reason for studying at home, so 'so' correctly shows cause and effect. A compound sentence also needs a comma before the conjunction. The other options use the wrong connector or omit punctuation.

Question 18Reading

Read this paragraph: 'The museum's new exhibit features tools used by early farmers. Visitors can try a hand plow and grind grain. Guides explain how each tool was made.' Who would find this exhibit most useful?

  1. Someone planning a city bus route
  2. Someone looking for cooking recipes
  3. Someone learning about historical farming methods Correct answer.
  4. Someone studying modern car engines

Explanation

The exhibit focuses on tools and methods of early farmers, so it best serves someone interested in historical farming. The reader must connect the described content to an audience. The other options relate to topics the paragraph never mentions.

Question 19Reading

Read this sentence: 'The scientist's findings were preliminary, so other researchers planned to repeat the experiment.' What does 'preliminary' mean here?

  1. Dangerous and illegal
  2. Final and proven
  3. Early and not yet confirmed Correct answer.
  4. Expensive and rare

Explanation

The plan to repeat the experiment shows the findings are not yet settled. 'Preliminary' means coming before the main or final stage. Context clues about repeating the work support this meaning.

Question 20Reading

Read this passage: 'The team lost its first three games. Instead of giving up, the players reviewed game footage each week and practiced their weakest skills. By the season's end, they had won five straight games.' Which statement best expresses the lesson of the passage?

  1. Hard work and reflection can lead to improvement. Correct answer.
  2. Winning is mostly a matter of luck.
  3. Losing early games makes a season a failure.
  4. Teams should avoid reviewing their mistakes.

Explanation

The team improved after studying footage and practicing weak skills, which shows effort and reflection paying off. The lesson should capture the cause of their turnaround. Options that dismiss practice or focus on luck miss the passage's emphasis.

Question 21Reading

A form states: 'Applicants must submit two references and a resume by March 1. Late applications will not be reviewed.' An applicant submits one reference on February 28. What is the result according to the form?

  1. The application will be reviewed early.
  2. The application is complete and on time.
  3. The application was submitted too late.
  4. The application is missing a required reference. Correct answer.

Explanation

The form requires two references, and the applicant supplied only one, so the application is incomplete even though it arrived before the deadline. The reader must check both the deadline and the required items. Being on time does not fix a missing document.

Question 22Reading

Read this passage: 'Advocates say the new bike lanes make streets safer for cyclists. Critics argue the lanes remove parking spaces that local shops depend on. The council will vote next month.' Which statement best describes the passage?

  1. It proves that bike lanes are always safe.
  2. It explains how to build a bike lane.
  3. It presents two opposing views on a proposal. Correct answer.
  4. It reports that the council has already voted.

Explanation

The passage gives supporters' reasons and critics' concerns before noting an upcoming vote, which presents two sides of an issue. Recognizing opposing viewpoints is a key reading skill for balanced reports. The passage does not settle the debate or describe construction.

Question 23Reading

Read this sentence: 'The mayor's announcement was met with cautious optimism; residents welcomed the plan but worried about its cost.' What does the semicolon do in this sentence?

  1. It shows that a word has been omitted.
  2. It introduces a list of items.
  3. It joins two closely related complete ideas. Correct answer.
  4. It marks a direct quotation.

Explanation

A semicolon can link two independent clauses that are closely related in meaning. Here both parts are complete ideas about residents' mixed reaction. Lists, omissions, and quotations use other punctuation marks.

Question 24Reading

Read this passage: 'The study found that students who read for twenty minutes daily scored higher on vocabulary tests. However, the researchers noted that students who choose their own books may read more willingly than those assigned texts.' Which conclusion is best supported?

  1. Assigned texts are always better for students.
  2. Vocabulary tests should be eliminated.
  3. Reading for twenty minutes guarantees top scores.
  4. Daily reading is linked to stronger vocabulary. Correct answer.

Explanation

The passage reports a link between daily reading and higher vocabulary scores, which supports a cautious conclusion. The word 'linked' matters because the study shows an association, not a guarantee. The other options overstate or contradict the findings.

Question 25Reading

Read this paragraph: 'The author describes the abandoned factory in detail: rusted gears, cracked windows, and vines creeping through the roof. She notes that neighbors once worked there and still recall its noise.' What is the main effect of these details?

  1. They compare the factory to a school.
  2. They argue that the factory should reopen.
  3. They create a sense of history and loss. Correct answer.
  4. They explain how factories are built.

Explanation

The decayed images combined with neighbors' memories create a mood of history and loss. Details about the past give the abandoned building emotional weight. The paragraph does not explain construction, argue for reopening, or compare the factory to a school.

Question 26Reading

Read this sentence: 'The volunteers painted the fence, and they cleaned the park.' Which word in the sentence is a pronoun?

  1. park
  2. fence
  3. they Correct answer.
  4. painted

Explanation

A pronoun is a word that replaces a noun. In this sentence, 'they' stands in for 'the volunteers,' so it is the pronoun. The other words are a verb ('painted') and nouns ('fence,' 'park').

Question 27Reading

Read this sentence: 'The hikers packed water, snacks, and a map.' What does the comma after 'snacks' do?

  1. It introduces a direct quotation.
  2. It joins two complete sentences.
  3. It shows that a word is missing.
  4. It separates items in a list. Correct answer.

Explanation

Commas are used to separate items in a series so readers can tell where one item ends and the next begins. Here the comma after 'snacks' separates the second item from the third item in the list. It does not join sentences, mark omissions, or introduce a quotation.

Question 28Reading

Read this notice: 'The pool will be closed for repairs from Monday to Wednesday. It will reopen on Thursday at 6 a.m.' When will the pool reopen?

  1. Monday at 6 a.m.
  2. Thursday at 6 a.m. Correct answer.
  3. Thursday at 6 p.m.
  4. Wednesday at 6 a.m.

Explanation

The notice states that the pool reopens on Thursday at 6 a.m. after being closed from Monday to Wednesday. The closing period ends before Thursday morning, so the reopening time is Thursday at 6 a.m. The other choices either fall during the closure or give the wrong time of day.

Question 29Reading

Read this sentence: 'The instructions were clear; ______, everyone finished the task quickly.' Which word best fills the blank?

  1. therefore Correct answer.
  2. otherwise
  3. meanwhile
  4. however

Explanation

The first part of the sentence gives a cause-clear instructions-and the second part gives a result-finishing quickly. The transition word 'therefore' signals that the second idea follows logically from the first. The other choices suggest contrast, simultaneous time, or a condition, which do not fit the cause-and-effect relationship.

Question 30Reading

Read this sentence: 'The documentary was so ______ that many viewers watched it twice.' Which word best completes the sentence?

  1. captivating Correct answer.
  2. boring
  3. lengthy
  4. confusing

Explanation

The second half of the sentence says that many viewers watched the documentary twice, which suggests they found it very engaging. 'Captivating' means holding attention strongly, so it fits the positive result described. The other adjectives would not logically explain why people chose to watch again.

Question 31Reading

Read this paragraph: 'The school garden began as a small project. Students planted herbs in two raised beds. By the next spring, the garden had expanded to include vegetables and a compost bin.' What is the main idea of the paragraph?

  1. Compost bins are useful for gardens.
  2. The school garden grew larger over time. Correct answer.
  3. Students prefer vegetables to herbs.
  4. Herbs are easy to grow in raised beds.

Explanation

The paragraph traces the school garden from a small project with herbs to a larger garden with vegetables and a compost bin. The main idea is therefore that the garden expanded over time. The other choices focus on minor details or make comparisons the paragraph does not support.

Question 32Reading

Read this sentence: 'The runner crossed the finish line and raised her arms in triumph.' What does the word 'triumph' suggest about the runner?

  1. She was happy about winning. Correct answer.
  2. She was unsure of the results.
  3. She was injured during the race.
  4. She was tired after the race.

Explanation

The word 'triumph' means a victory or great success, and raising her arms suggests celebration. Together these clues show that the runner was pleased about winning or succeeding. The other choices describe negative or uncertain feelings that do not match the celebratory action.

Question 33Reading

Read this sentence: 'The museum's new exhibit features tools used by early farmers. Visitors can try a hand plow and grind grain.' Which sentence best summarizes the exhibit?

  1. It sells tools to visitors.
  2. It lets visitors experience old farming tools. Correct answer.
  3. It displays modern farm machines.
  4. It explains how to become a farmer.

Explanation

The exhibit shows tools from early farmers and invites visitors to try them, such as a hand plow and grinding grain. A good summary captures both the historical tools and the hands-on activity. The other choices misstate the time period, the purpose, or the action.

Question 34Reading

Read this paragraph: 'The city council debated a proposal to add more streetlights. Supporters said brighter streets would reduce accidents. Opponents worried about the cost and light pollution.' What is the paragraph mainly about?

  1. The cost of light pollution
  2. How to install streetlights
  3. Why accidents happen at night
  4. Two sides of a streetlight proposal Correct answer.

Explanation

The paragraph presents both supporters' reasons and opponents' concerns about adding streetlights. The main focus is the debate between these two viewpoints. The other choices pick up on single details or introduce topics not covered.

Question 35Reading

Read this sentence: 'The scientist's findings were preliminary, so other researchers planned to repeat the experiment.' What does 'preliminary' most nearly mean?

  1. complex
  2. final
  3. early Correct answer.
  4. false

Explanation

The word 'preliminary' describes something that comes before the main or final stage. The sentence supports this because other researchers want to repeat the experiment, suggesting the results are not yet confirmed. 'Early' is the closest match among the choices.

Question 36Reading

Read this passage: 'The team lost its first three games. Instead of giving up, the players reviewed game footage each week and practiced a new play. By the end of the season, they had won five of their last six games.' What is the message of the passage?

  1. Losing early games is unavoidable.
  2. Teams should change coaches after losing.
  3. Watching footage is more useful than practicing.
  4. Practice and review can lead to improvement. Correct answer.

Explanation

The passage shows the team improving after they reviewed footage and practiced a new play. The outcome-winning five of the last six games-supports the idea that effort and practice pay off. The other choices are not stated or are contradicted by the passage.

Question 37Reading

Read this sentence: 'The mayor's announcement was met with cautious optimism; residents welcomed the plan but worried about the cost.' What does 'cautious optimism' mean here?

  1. Anger about the announcement
  2. Hopeful but with some doubts Correct answer.
  3. Indifference to the plan
  4. Complete rejection of the plan

Explanation

The semicolon explains the phrase: residents welcomed the plan, which shows optimism, but they worried about the cost, which shows caution. Together the words mean hopeful with reservations. The other choices describe feelings that are too negative or too neutral.

Question 38Reading

Read this passage: 'Some cities are replacing parking lots with small parks. These parks cool the air, absorb rainwater, and give residents a place to relax.' Which sentence best states the author's point?

  1. Parking lots are more useful than parks.
  2. Cities should remove all parking lots.
  3. Residents prefer parks to parking lots.
  4. Small parks offer several benefits to cities. Correct answer.

Explanation

The passage lists three benefits of small parks: cooling the air, absorbing rainwater, and providing relaxation space. The author's point is that these parks are beneficial. The other choices go beyond the text or contradict it.

Question 39Reading

Read this paragraph: 'The author describes the abandoned factory in detail: rusted gears, cracked windows, and vines creeping through the roof. These images suggest that nature is slowly reclaiming the building.' What is the purpose of the details in the paragraph?

  1. To explain how factories operate
  2. To compare two different factories
  3. To create a vivid picture that supports an idea Correct answer.
  4. To persuade readers to visit the factory

Explanation

The details-rusted gears, cracked windows, and vines-paint a clear picture of decay. They are used to support the idea that nature is reclaiming the building. The other choices describe purposes the details do not serve.

Question 40Reading

Read this sentence: 'Although the trail was steep, the hikers reached the summit before sunset.' Which relationship does 'although' show between the two parts?

  1. Addition
  2. Sequence
  3. Contrast Correct answer.
  4. Cause and effect

Explanation

'Although' introduces an idea that contrasts with the main clause: the trail was steep, yet the hikers still reached the summit. It signals that the second part happened despite the first. The other choices describe relationships that do not match this meaning.

Question 41Reading

Read this passage: 'The study found that students who read for twenty minutes daily scored higher on vocabulary tests. However, the researchers noted that the study did not prove that reading caused the higher scores.' What caution do the researchers make?

  1. Vocabulary tests are unreliable.
  2. The link between reading and scores is not proven to be causal. Correct answer.
  3. Reading for twenty minutes is too long.
  4. Students should not read daily.

Explanation

The researchers point out that their study showed a connection but did not prove that reading caused the higher scores. This is a caution about confusing correlation with causation. The other choices misstate the caution or add claims not in the passage.

Question 42Reading

Read this notice: 'Applications must be submitted online by 5 p.m. on Friday. Late applications will not be considered.' What can a reader conclude?

  1. Applicants may submit by phone.
  2. Paper applications are accepted.
  3. The deadline may be extended.
  4. Applications sent after 5 p.m. Friday will be rejected. Correct answer.

Explanation

The notice states a firm deadline and says late applications will not be considered. Therefore, an application sent after 5 p.m. on Friday will be rejected. The other choices contradict the notice or add information it does not contain.

Question 43Reading

Read this sentence: 'The company's profits rose sharply after it redesigned its packaging.' Which word is the subject of the sentence?

  1. company's
  2. packaging
  3. profits Correct answer.
  4. rose

Explanation

The subject is the noun or noun phrase that performs the action or is described by the verb. Here, 'profits' is what rose, so it is the subject. 'Company's' is a possessive modifier, 'rose' is the verb, and 'packaging' is part of a prepositional phrase.

Question 44Reading

Read this paragraph: 'The festival will feature local musicians, food trucks, and art displays. Organizers expect a large crowd, so attendees are encouraged to carpool or take public transit.' What is the main purpose of the paragraph?

  1. To inform attendees about the festival and transportation Correct answer.
  2. To complain about traffic
  3. To review last year's festival
  4. To persuade musicians to perform

Explanation

The paragraph tells readers what the festival offers and advises them on how to get there because of expected crowds. Its purpose is to inform attendees about both the event and transportation options. The other choices describe purposes not supported by the text.

Question 45Reading

Read this passage: 'Many people believe that goldfish have a three-second memory. In fact, research has shown that goldfish can remember information for months and can be trained to respond to sounds.' What is the author's main purpose?

  1. To compare goldfish with other pets
  2. To entertain readers with a fish story
  3. To explain how to train goldfish
  4. To correct a common misconception Correct answer.

Explanation

The passage begins with a common belief and then presents research that contradicts it. The author's purpose is to correct the misconception about goldfish memory. The other choices do not capture the contrast between belief and evidence.

Question 46Reading

Read this sentence: 'The committee's recommendation was not to reject the plan but to revise it.' What does the sentence mean?

  1. The committee rejected the plan.
  2. The committee ignored the plan.
  3. The committee approved the plan without changes.
  4. The committee wanted the plan changed, not discarded. Correct answer.

Explanation

The 'not...but...' structure contrasts two actions: rejecting the plan and revising it. The committee chose revision over rejection, which means they wanted changes rather than discarding the plan. The other choices misread the contrast.

Question 47Reading

Read this paragraph: 'The article notes that the new policy reduced wait times at the clinic. However, it also points out that the clinic hired more staff at the same time. The article concludes that the policy's effect cannot be isolated.' What is the article's reasoning?

  1. Two changes happened together, so the cause is unclear. Correct answer.
  2. More staff caused the shorter waits.
  3. The policy definitely caused the shorter waits.
  4. Wait times did not actually change.

Explanation

The paragraph describes two changes occurring at once-the new policy and more staff-and concludes that the policy's effect cannot be isolated. This is reasoning about confounding factors. The other choices either overstate the evidence or contradict the paragraph.

Question 48Reading

Read this sentence: 'The proposal, which many residents supported, was ultimately tabled until the next meeting.' What does 'tabled' mean in this context?

  1. Presented for the first time
  2. Postponed for later discussion Correct answer.
  3. Rejected permanently
  4. Approved immediately

Explanation

The phrase 'until the next meeting' signals that the proposal was set aside to be discussed later. In this context, 'tabled' means postponed. The other choices describe actions that conflict with the idea of delaying until a future meeting.

Question 49Reading

Read this passage: 'The company claims its new battery lasts twice as long as competitors' batteries. The claim is based on a test the company designed and ran itself. Independent tests have not yet confirmed the results.' What is the best evaluation of the company's claim?

  1. The claim is proven because the company tested it.
  2. The claim is false because no test was done.
  3. The claim is questionable because the test was not independent. Correct answer.
  4. The claim is irrelevant to consumers.

Explanation

The passage notes that the company designed and ran its own test and that independent tests have not confirmed the results. This raises concerns about bias, making the claim questionable rather than proven. The other choices misstate the evidence or dismiss the claim without support.

Question 50Reading

Read this paragraph: 'The city's bike-share program was designed to reduce traffic. After two years, the number of riders had grown steadily. However, traffic levels remained about the same. The program's supporters argue that traffic would have been worse without it.' What is the weakness in the supporters' argument?

  1. It ignores the growth in the number of riders.
  2. It relies on an untestable claim about what would have happened otherwise. Correct answer.
  3. It assumes that traffic is the only problem.
  4. It uses data from only two years.

Explanation

The supporters claim traffic would have been worse without the program, but this is a hypothetical that cannot be directly tested. That makes the argument weak because it cannot be proven with the available evidence. The other choices are not the main weakness described.