Bunuel wrote:
The success of recent class-action lawsuits filed against three large mail order book clubs
have led to a revision in the contractual language used by similar businesses.
A. have led to a revision in the contractual language used by similar businesses
B. has led to a revision in the contractual language used by similar businesses
C. has led them to a revision in the contractual language used by similar businesses
D. leads them to a revision used in the contractual language by similar businesses
E. have led to the revising of the contractual language used by similar businesses
VERITAS PREP OFFICIAL SOLUTION:
The presence of singular vs. plural verbs - "has led" vs. "have led" - in the first words of each answer choice should indicate to you that subject-verb agreement is a likely decision point on this question. And when you're assessing subject-verb agreement it is helpful to eliminate modifying phrases as you "slash and burn" away the excess description to get to the root of the sentence.
Here "of recent class-action lawsuits..." is a prepositional modifier describing "the success." So "the success" is the subject of the sentence. Because "the success" is singular you can eliminate the plural verb "have led" in choices (A) and (E).
The difference between (B) and (C) is that choice (C) adds a pronoun "them," so you should determine whether "them" has a logical antecedent. Note that neither of the plural nouns that could be the antecedent of "them" ("lawsuits" and "book clubs") could logically be what is "led to the revisions.' The book clubs being sued are not part of "similar businesses" (they're the original businesses) and "lawsuits" is part of the subject of the sentence so it wouldn't be also part of the object (e.g. "the success of the lawsuits has led the lawsuits to a revision..."). So "them" is incorrect and you can eliminate (C).
Choice (D) includes the same "them" pronoun error and also adds. "The success of the recent lawsuits leads to a revision..." suggests that this is a common occurrence (such as "water flows downhill") when the word "recent" and the specificity of three particular lawsuits demonstrates that this is a temporary situation. Therefore "leads" is incorrect.
Choice (B) uses proper subject-verb agreement and verb tense without introducing any other errors, and is therefore correct.