According to the Tristate Transportation Authority, making certain improvements to the main commuter rail line would increase ridership dramatically. The authority plans to finance these improvements over the course of five years by raising automobile tolls on the two highway bridges along the route the rail line serves. Although the proposed improvements are indeed needed, the authority's plan for securing the necessary funds should be rejected because it would unfairly force drivers to absorb the entire cost of something from which they receive no benefit. Which of the following, if true, would cast the most doubt on the effectiveness of the authority's plan to finance the proposed improvements by increasing bridge tolls? (A) Before the authority increases tolls on any of the area bridges, it is required by law to hold public hearings at which objections to the proposed increase can be raised. (B) Whenever bridge tolls are increased, the authority must pay a private contractor to adjust the automated toll-collecting machines. (C) Between the time a proposed toll increase is announced and the time the increase is actually put into effect, many commuters buy more tokens than usual to postpone the effects of the increase. (D) When tolls were last increased on the two bridges in question, almost 20 percent of the regular commuter traffic switched to a slightly longer alternative route that has since been improved. (E) The chairman of the authority is a member of the Tristate Automobile Club that has registered strong opposition to the proposed toll increase.
答案选D，我选了C。虽然我觉得D有道理，但是C选项——commuter提前买了很多token以延迟涨价的影响，也是对这个计划有效性的一种影响啊！而D选项说有20％的人会换道，那还有80％的人在走原来这条涨了路费的道路。两个选项都有可取之处，只是不知道GMAC怎么就确定应该是D选项。 恳请nn指点！ | 
