求助一道prep削弱题

worry1a2a

prep.A major impediment to wide acceptance of electric vehicles even on the part of people who use their cars almost exclusively for commuting is the inability to use electric vehicles for occasional extended trips.  In an attempt to make purchasing electric vehicles more attractive to commuters, one electric vehicle producer is planning to offer customers three days free rental of a conventional car for every 1,000 miles that they drive their electric vehicle.

Which of the following, if true, most threatens the plan's prospects for success?

(A) Many electric vehicles that are used for commercial purposes are not needed for extended trips.
(B) Because a majority of commuters drive at least 100 miles a week, the cost to the producer of making good the offer would add considerably to the already high price of electric vehicles.
(C) The relatively long time it takes to recharge the battery of an electric vehicle can easily be fitted into the regular patterns of car use characteristic of commuters.
(D) Although electric vehicles are essentially emission-free in actual use, generating the electricity necessary for charging an electric vehicle's battery can burden the environment.
(E) Some family vehicles are used primarily not for commuting but for making short local trips, such as to do errands

答案是B。可是没弄懂为什么跟cost有关。。。谢谢！

huangyouhuifei

同问~~~
我的理解：
目的：吸引顾客
措施：每开1000mile的电车，就可以免费租用3天普通车
B说：多数人每周至少开100mile，制造商提供这3天优惠而发生的成本，将会增加电车本已很高的价格
意思就是说每开1000mile就可免费租三天，而多数人每周开100mile，10周多，也就是说两个半月就可以免费租车，这未免也太频繁了吧！这将增加制造商的成本，而这些成本最终还是被加在了车的价格上，价格一上升，吸引力明显降低。所以措施达不到目的。
个人想法，求高人指点~~

sdcar2010

Because high cost would run counter to the goal of making purchasing electric vehicles more attractive to commuters.