这道题我真的不知道它在说什么, 很晕啊!! 可以帮我看看吗~~~~谢谢!!

37. 

Capuchin monkeys in Venezuela often rub a certain type of millipede into their fur.  Secretions of these millipedes have been shown to contain two chemicals that are potent mosquito repellents, and mosquitoes carry parasites that debilitate the capuchins.  The rubbing behavior is rare except during the rainy season, when mosquito populations are at their peak.  Therefore, the monkeys probably rub the millipedes into their fur because doing so helps protect them against mosquitoes.

Which of the following would it be most useful to determine in order to evaluate the argument?

(A) Whether the two chemicals provide any protection for the millipedes against their own predators
(B) Whether the type of millipede used by the capuchin monkeys in Venezuela is found in other parts of the world
(C) Whether animals other than capuchins rub insects of any kind into their fur
(D) Whether the only time the millipedes are readily available to the capuchins is during the rainy season
(E) Whether secretions of any other insects accessible to the capuchins contain chemicals that repel mosquitoes

答案是D~~~~帮帮我吧!~~~~谢谢

題目條件: (1)猴子在雨季時把節肢動物弄到身上  (2) 雨季時蚊子最多

推論：猴子此行為是為了防蚊

要 evaluate 此推論

(A) irrelevant (millipedes' predators)

(B) irrelevant (in other parts of the world)

(C) irrelevant (other animal)

(D) YES => 猴子僅有雨季時可以找到 millipedes，不一定是因為雨季蚊子多有關 (有他

因, weaken 原推論)

     NO => 猴子此行為是為了防蚊 (排除他因, support 原推論)

(E) irrelevant (other insects' chemicals)

即使其他昆蟲亦分泌此化學物質，和猴子此行為也無關

这题是说  millipede可以防止蚊子啥的， Capuchin monkeys只有在蚊子多的时节才把millipede往身上擦，这个特殊的时候才擦可以证明 Capuchin monkeys是用它来防止蚊子的

但如果millipede只有在rainy season 这个特殊的时节才可以被Capuchin monkey抓到利用呢？