This is an "evaluate the argument" question. In a sense, we're looking for an assumption, just in a different format that in assumption questions. This argument claims that, because U.S. cities are not bicycle-friendly, U.S. cities cannot implement European-style bicycle sharing programs. Each choice has two possible outcomes ("whether" it is the case, or it is not the case), so we're looking for a choice in which one of the outcomes would have an impact on the argument. Consider each in turn:

(A) This is correct. If an increase in the number of bicyclists could change attitudes toward bicyclists, a bicycle-sharing program may well solve the problem suggested in the argument.
(B) This is not important; it doesn't matter if people (car-drivers or not) can operate bicycles if cities are too hostile to bicyclists.
(C) This is outside the scope. The problem described in the passage is not the lack of bicycle lanes, it is the culture of U.S. cities.
(D) As with (B), this is not relevant, since it doesn't address the issue of hostility to bicyclists.
(E) This comparison is outside of the scope, as we're concerned only with the viability of bicycle-sharing programs in large U.S. cities.