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 zoo employee who develops a serious animal-induced allergy is very likely to switch to some other occupation.
A zoo employee is more likely than a person in the general population to keep one or more animal pets at home
The percentage of the general population whose level of exposure to animals matches that of a zoo employee is quite small.
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.
Zoo employees seldom wear protective gear when they handle animals in their care.