一道assumption题，觉得答案很怪，最近CR很不给力啊

wynyy2000

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.
条件：动物园管理员中，30%都会有动物引起的过敏      
结论：其他人如果也像管理员一样长时间接触动物，那么过敏会更多

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. 不懂，对结论有什么影响？
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
我在做题时，看到A就排除了

Joseph_lin

原本如果general population的人像动物管理员一样经常接触动物的话，也就会有30%的人过敏，而如果有原本的动物园的管理员不做管理员了，加入到general population中去了的话，那么这个general population中的人过敏人数的比例就会大于30%了

sdcar2010

Premise: Around 30% of current zoo employees have animal-induced allergy.

Conclusion: If people spend time with animals as long as an average zoo employee, the percentage of them who would develop animal-induced allergy is much higher than 30%.

Don't you think it is odd that the general population would have a higher chance to develop animal-induced allergy than zoo employees??? This is a paradox!

Well, if A is true, the conclusion holds and the paradox is explained.  A says that a zoo employee can easily switch jobs to other professions.  Therefore, a fast turnover at the zoo prevents some zoo employees from developing animal-induced allergies and being counted in the zoo employee category. This effectively leads to a lower percentage in allergy cases for zoo employees than it should be for people who spend long time everyday with animals.