Question

Select all items that describe kinds of externalities.

A. secondhand smoke

B. air pollution from trucks

C. unclean water from fertilizers

D. spillovers from medical research

Answer 1

I believe that the items that describe kinds of externalities are b) air pollution from trucks and c) unclean water from fertilizers.
I am not completely sure, though. 

Answer 2

The answer is air pollution from trucks and unclean water from fertilizers