Sajjad1994
A thesaurus can be a useful tool for
writers, providing he knows how to use it correctly.
(A) writers, providing he knows how to use it
(B) writers, providing he knows how to use such a book
(C) a writer, providing he knows how to use them
(D) writers, providing she knows how to use it
(E) writers, providing they know how to use it
Source: Master GMAT
OFFICIAL EXPLANATION
The correct answer is (E). A pronoun and the noun to which it refers (called the
antecedent) should be consistent; both should be either singular or plural. In the original sentence, however, the singular pronoun
he is inconsistent with its plural antecedent
writers. Among the four alternatives, only choices (C) and (E) fix this problem. In choice (C), both are singular, while in choice (E) both are plural; either is acceptable. Choice (C), however, creates another pronoun antecedent error. Notice that it replaces the singular pronoun
it with the plural
them. Since the intended antecedent is
thesaurus, which is singular, the plural pronoun
them is incorrect, and you can eliminate choice (C). Choice (E) is the best version of the underlined part; it fixes the problem with the original version without creating any new errors.