Bunuel
Each of the factory
owners that felt that pollution was a severe problem wanted a drastically reformed system of industrial waste disposal in the area.
(A) owners that felt that pollution was a severe problem
(B) owners which felt that pollution was a severe problem
(C) owners who felt that pollution was a severe problem
(D) owners who felt that pollution to be a severe problem
(E) owners, feeling that pollution was a problem quite severe,
KAPLAN OFFICIAL EXPLANATION:
The pronoun in question is that and it refers to the factory owners, but the problem is that that is a pronoun to be used only for things; people must be referred to by the pronoun who. You can eliminate (A) and (B). The remaining choices differ at the end. (D) clearly grates on the ear and can be removed. A problem quite severe in (E) is rather too cute, and the choice also distorts the meaning of the sentence (it gives the impression that all of the owners are worried about pollution, which is not the meaning of the original sentence). Go with (C).