We are given a civil engineer’s argument and asked to find the choice that most seriously weakens the reasoning.
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Argument Recap:
Premise:
• Trade between northern and southern cities has stagnated.
• There are few reliable methods of transporting goods between them.
Conclusion:
• To spur economic growth, we must build a freeway system that passes no more than five miles from each city.
So the engineer is assuming:
• The only way to spur trade is by building a freeway that passes very close (≤ 5 miles) to each city.
• Proximity of freeway (within 5 miles) is necessary for trade to improve.
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Let’s evaluate the answer choices:
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A. Building a freeway system that passes as much as ten miles from each city would be sufficient to greatly increase trade...
• ✅ Directly weakens the engineer’s claim.
• If 10 miles is sufficient, then the “no more than 5 miles” condition is unnecessarily strict and not required to spur trade.
✅ Strongly weakens.
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B. There are other, more important causes for the lack of trade...
• This brings in other causes — but the engineer’s argument is focused on one solution.
• While this slightly weakens the idea that a freeway would solve everything, it doesn’t directly refute the logic about freeway proximity.
❌ Less directly weakening.
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C. The state’s infrastructure budget is not currently large enough...
• This is a practical obstacle, not a flaw in reasoning.
• We’re asked to weaken the reasoning, not the feasibility.
❌ Irrelevant to reasoning.
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D. Growth in commercial traffic is associated with closeness of the transportation system...
• This supports the engineer’s reasoning — proximity boosts trade.
❌ Strengthens, not weakens.
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E. Reliability of existing transport methods can be improved somewhat without building a freeway...
• This suggests alternative solutions, but doesn’t necessarily challenge the effectiveness of a close freeway.
• It’s a mild weakening — but not as strong as A.
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✅ Final Answer: A
It most directly challenges the assumption that a freeway must pass within 5 miles of each city to spur trade — and offers a less extreme alternative that would achieve the goal.