Bunuel wrote:
A technical proposal has been advanced for a transportation system in individuals travel through tubes in pressurized capsules on a cushion of air. One individual in a capsule, according to the proposal, will be able to travel up to ten times as faster as an automobile on a highway. Such a futuristic means of conveyance would surely be thrilling for individuals, but the cost of building the new transport tube between two major cities has been estimated at six billion dollars. Even if this doubtful cost figure is accurate, it represents a waste of money. The cost of maintaining the existing roads between the two cities in question is negligible compared to the cost of building the tube, and those six billion dollars can be dedicated to more vital public works projects.
Which of the following, if true, most severely weakens the argument presented above?
A. The transport tube can be built between only two cities initially, and then further decisions can be made based on the outcome of that project.
B. The cost of building the transport tube between cities after the first two connected will be less than the cost of building the original route.
C. The technology developed in the course of the new transportation system could be applied to most vital public works projects, reducing their costs to negligible levels.
D. Developing the new transport system between the two cities identified will allow the government to stop spending funds on maintaining the roads between those two cities.
E. For city dwellers who do not own cars, traveling by road rather than by the new transport system is not an option.
Official Explanation
Reading the question: this argument contains a lot of introductory material and bluster. The important stuff starts with "it represents a waste of money," the conclusion. The key piece of evidence is the cost comparison: maintaining existing roads vs. building the tube. Even if that evidence is true, as we take it to be, there might be benefits to this tube idea that have not been considered within the argument. We'll take that observation and use "new benefit," a tube-positive idea, as our filter for an answer choice that weakens the argument.
Applying the filter: choice (A) is tube-negative, so it doesn't pass the filter. Choice (B) is tube-positive, but barely, and it's not a new benefit. (B) is out. (C) is a big new benefit: looks good. (D) is not much of a new benefit, since we are told the cost of maintaining the roads is negligible. (D) is out. (E) is better than the other wrong answers, but it doesn't clearly establish a benefit.
Logical proof: using the negation test, we can observe that if the new technology for the tube system had no application outside this project, then the tube project would be harder to justify. The negated (C) strengthens the argument, confirming that the non-negated (C) weakens the argument.
The correct answer is (C).