Critical Reasoning

It might seem that an airline could increase profits by reducing airfares on all its flights in order to encourage discretionary travel and thus fill planes. Offers of across-the board discount fares have, indeed, resulted in the sale of large numbers of reduced-price tickets. Nevertheless such offers have, in the past, actually cut the airline’s profits.
Which one of the following, if true, most helps to resolve the apparent discrepancy described above?
(A) Fewer than 10 percent of all air travelers make no attempt to seek out discount fares.
(B) Fares or trips between a large city and a small city are higher than those for trips between two large cities even when the distances involved are the same.
(C) Across-the-board discounts in fares tend to decrease revenues on flights that are normally filled, but they fail to attract passengers to unpopular flights.
(D) Only a small number of people who have never before traveled by air are persuaded to do so on the basis of across-the board discount fares.
(E) It is difficult to devise an advertising campaign that makes the public aware of across-the-board discount fares while fully explaining the restrictions applied to those discount fares.
Please explain why B is wrong.

C