求解一题cr

Mayor: Since the time that our city's central streetcar line was built ten years ago, over $4 billion of private development has occurred within one-half kilometer of the line. This private development increased the city's tax revenue over those ten years just enough to compensate for the cost of building that line. So our city's proposed development of an eastside streetcar line through a similar neighborhood should also pay for itself within ten years.

Which of the following is an assumption the mayor's argument requires?

(A) Over the past ten years, private developers have invested in significant development within one-half kilometer of the proposed eastside streetcar route. (B) Littleifanyoftheprivatedevelopmentreferredtowouldhaveoccurredifthestreetcar line had not been built. (C) One benefit to the city from the central streetcar line has been the increased tax revenue from private development in other parts of the city. (D) Lessthan$4Billionofprivatedevelopmenthasoccurredmorethanone-halfkilometer from the central streetcar line over the past ten years. (E) The central streetcar line did not cost the city significantly more to build than the eastside streetcar line will cost. 

这题难道不是类比推理吗? 因为第一条line在10年内收回成本所以新的line也可以. 为什么答案不选E?

求解答,谢谢