Bunuel
In Metroville, the KP subway line follows the riverfront from downtown to the neighborhoods surrounding the university. No matter how many trains the subway runs on the KP line, there are always congestion and delays on the KP line. The subway submitted a proposal for an alternate subway line that would travel from downtown to the neighborhoods surrounding the university via the inland neighborhoods, hoping to draw some of the congestion from the KP line. The city hired urban planning consultants who concluded the subway's proposal of a new line would not reduce commuter congestion on the KP line.
Which of the following, if true, most helps to explain the urban planning consultants' position?
(A) Construction of a new subway line would involve constructing a number of new stations throughout the city.
(B) The city buses that run along the river between downtown and the university would be more attractive to commuters than an inland subway line.
(C) Construction of a new subway line would inevitably stimulate the growth of new business and restaurants along that line, especially in the vicinity of the stations of that new line.
(D) Some commuters have reported having to wait as long as half an hour to board a train on the KP line.
(E) The most popular after-work destinations, such as riverfront restaurants and bars as well as the ballpark, would only be accessible by the current KP line.
Official Explanation
The KP line is crowded, and the city wants to solve this problem by building a second line further inland. The urban planning consultants conclude this will not help. We need some reason why, even with the presence of the second line, the first line would remain congested. We want to strengthen/justify the urban planning consultants' conclusion.
(E) is the credited response. If all the places people want to go are on the KP line, then building another line somewhere else won't draw many passengers from the KP line to the new line.
(A) is irrelevant. Of course a new line would involve new stops, but this doesn't explain why the new line wouldn't draw passengers from the KP line.
(B) is a weak strengthener. It suggests as a possibility that the corridor along the river is more attractive than an inland route --- that's one reason the buses would be more popular, but not the only one. Because this is unclear, it's not the most powerful strengthener.
(C) weakens the urban planning consultants' conclusion: if there are attractive destinations along the new line, passengers would be drawn from the KP line to the new line. This response weakens the conclusion that we need to strengthen.
(D) emphasizes the nature of the problem the city is trying to solve, but it doesn't explain why the suggested solution of a new inland line wouldn't work.