请大牛指点一下，好像A根本不搭啊！

斯巴达

People who have spent a lot of time in contact with animals often develop animal-induced allergies, some of them quite serious. In a survey of current employees in major zoos, about 30 percent had animal-induced allergies. Based on this sample, experts conclude that among members of the general population who have spent a similarly large amount of time in close contact with animals, the percentage with animal-induced allergies is not 30 percent but substantially more.
Which of the following, if true, provides the strongest grounds for the experts’ conclusion?

A.    A zoo employee who develops a serious animal-induced allergy is very likely to switch to some other occupation.  （不理解这话意思，转换到其它职业，啥意思）
B.    A zoo employee is more likely than a person in the general population to keep one or more animal pets at home
C.    The percentage of the general population whose level of exposure to animals matches that of a zoo employee is quite small.
D.    Exposure to domestic pets is, on the whole, less likely to cause animal-induced allergy than exposure to many of the animals kept in zoos.
E.    Zoo employees seldom wear protective gear when they handle animals in their care.

爆炒拖鞋

先说结论：砖家们结论是和动物呆的越久。染病的几率远比平均的30%高。
但是为什么之前测算的是30%捏？

因为A。染病的跳槽走了。。。就降低了总几率。

斯巴达

switch的意思是啥啊，我理解是动物员员工跳槽呢

Queeny11

原文说 总和动物接触会得一种病， 调查出动物园里 得病的有30% 结论是 总体来说得病的应该超过30%~~~~也就是肯定有得病的现在不在动物园里工作的啦。。
A说的就是这个意思。、