请教一道逻辑：街边消防报警电话取消

Springfield Fire Commissioner: the vast majority of false fire alarms
        are prank calls made anonymously from fire alarm boxes on street
        corners. Since virtually everyone has access to a private telephone,
        these alarm boxes have outlived their usefulness. Therefore, we
        propose to remove the boxes. Removing the boxes will reduce the
        number of prank calls without hampering people’s ability to report a fire.

Which of the following, if true, most strongly supports the claim that the
        proposal, if carried out, will have the announced effect?

A.    The fire department traces all alarm calls made from private telephones and records where they came from.

B.    Maintaining the fire alarm boxes costs Springfield approximately
        five million dollars annually.

C.    A telephone call can provide the fire department with more information about the
        nature and size of a fire than can an alarm placed
        from an alarm box.

D.    Responding to false alarms significantly reduces the fire department’s capacity for responding to fires.

E.     On any given day, a significant percentage of the public telephones
        in Springfield are out of service.

答案居然是C？

我选D，我的理解：

1大部分错误的火警都是来自于alarm boxes的匿名恶作剧电话，2因为每个人都有私人电话，alarm boxes 是没有必要的，3所以移除alarm boxes会在降低恶作剧电话的同时没有阻碍报警的能力（without hampering people’s ability to report a fire）

首先，因为恶作剧电话大多数来自alarm boxes，显然Removing the boxes will reduce the  number of prank calls是成立的
        ，文章结论的重点在于没有阻碍报警能力，那么D选项说明了这点，补充了Removing the boxes -not hamper people’s ability to report a fire中间的gap，所以是答案。

如果硬是强调要去支持Removing the boxes -reduce the  number of prank calls这条逻辑链，这里会出现一个gap，即那些打恶作剧电话的人不会“全部”（如果有一部分人转一样会是reduce）转用私人电话上打，A似乎为填补这个gap创造了条件，有支持的作用。但是support一般都是直接填补gap，只是创造了一个需要去发挥个人想象的条件，显然支持作用不如D

但答案为何时C啊？！！！

请NN帮忙解惑，非常感谢！

"首先，因为恶作剧电话大多数来自alarm boxes，显然Removing the boxes will reduce the  number of prank calls是成立的
        ，文章结论的重点在于没有阻碍报警能力，" 到这里你的推理都是正确的。

D全部在谈消防队应对火情，而没有涉及报案人报告火情，即不能证明“without hampering people’s ability to report a fire”。而C恰好是说明了报案人用私人电话报告火情比用alarm box更有效。

jameshoo，

衷心感谢你的解释，明白了。