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.

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.