gmatblast wrote:
The pesticide Azocide, introduced to central valley farms three
summers ago, has proven ineffective because other pesticides'
chemical compositions already in wide use neutralizing its
desired effect.
(A) because other pesticides' chemical compositions already
in wide use
(B) because of the chemical compositions of the pesticides
already in wide use
(C) due to other pesticides already in wide use, whose
chemical compositions have been
(D) since, due to the chemical compositions of other pesti-
cides already in use, those pesticides have been
(E) because of other pesticides and their chemical compo-
sitions already in use, which have been
A is wrong because it refers to compositions in wide use, not pesticides; also it is a sentence fragment.
B is wrong because the ineffectiveness is not caused by the "chemical compositions" of pesticides in wide use, but rather by the of "pesticides" in wide use. i.e., IMO the "wide use" should be emphasized rather than the "chemical composition" as the culprit.
C correct states that the problem is due to the wide use of the other pesticides -- explaining further that the chemical compositions of those pesticides have been neutralizing the effect.
D is wrong because it does not carry the implication that the "wide" use of the other pesticides is the crux of the problem
E is wrong for the same reason as above.