大全-20-15, help me....

-15.   In the United States, vacationers account for more than half of all visitors to what are technically called “pure aquariums” but for fewer than one quarter of all visitors to zoos, which usually include a “zoo aquarium” of relatively modest scope.

Which of the following, if true, most helps to account for the difference described above between visitors to zoos and visitors to pure aquariums?

(A) In cities that have both a zoo and a pure aquarium, local residents are twice as likely to visit the aquarium as they are to visit the zoo.

(B) Virtually all large metropolitan areas have zoos, whereas only a few large metropolitan areas have pure aquariums.

(C) Over the last ten years, newly constructed pure aquariums have outnumbered newly established zoos by a factor of two to one.

(D) People who visit a zoo in a given year are two times more likely to visit a pure aquarium that year than are people who do not visit a zoo.

(E) The zoo aquariums of zoos that are in the same city as a pure aquarium tend to be smaller than the aquariums of zoos that have no pure aquarium nearby.

why select B? Is USA consider Visitor is the foreigner of the area or city?

我的理解是，B中因为US比较少的城市有水族管，而很多的城市有动物园。那么水族馆的基数比较小，而动物园的比较大，则在同样数量的游客情况下，去水族馆的比例就会比较大，而去动物园的比较小。

请指正！

这是一道无聊题

vacationer指在度假的人。因为在度假时时间较多，当然往平时去不了的地方跑。所以造成纯水族馆（只有几个大城市有）主要旅客是度假者，而动物园（多数城市有）主要旅客是非度假者（平时可以去的人）。现象解释题。B解释了差别的原因。

我觉得这个题目出得很狡猾，很容易让人看错。

题目的意思是：vacationers / 参观水族馆的人 > 1/2

而 vacationers / 游览动物园的人 < 1/4

正如lawyer所说的，度假当然往平时去不了的地方跑。由于只有少数城市有纯的水族馆，所以吸引了很多度假的人，导致度假者在“参观水族馆的人”中比例高。

同意lawer的解释，但红字和答案结合起来还是不能解释该现象，还少一个条件：vacationer 度假往metropolitan跑！