In the selection from the silent spring, why are doctors in the town puzzled

This question is missing the options. I've found the complete question online. It is the following:

In the selection from "Silent Spring", why are doctors in the town puzzled?

A. More children are being born with birth defects.

B. People are being attacked more often by wild animals.

C. People are reacting more violently to insect stings.

D. More people are becoming sick from new kinds of illnesses.

In "Silent Spring", the doctors in the town are puzzled because:

D. More people are becoming sick from new kinds of illnesses.

Explanation:

"Silent Spring" is a book by Rachel Carson published in 1962. It raised important questions about the future of the planet as well as our own, focusing especially on the use of pesticides. Carson describes a silent and deadly reality, in which pesticides have affected nature's and humanity's well-being. At a certain point, the author describes concerned doctors. More and more people are getting sick with new types of diseases, resulting from the use of pesticides. Of course, such a terrible description annoyed the chemical industry, but Carson's book was still successful in drawing people's attention to environmental issues.