After all the research that has been conducted in the last 30 years,

KAPLAN OFFICIAL EXPLANATION

Step 1: Read the Original Sentence Carefully, Looking for Errors
Sometimes the subject of a clause will appear after the verb, as is the case in this sentence. In
the underlined subordinate clause, the subject is “a wealth” and the verb is “are”—and both are
underlined, so we must check for agreement. (The noun “reasons” cannot be the subject because
it is part of the prepositional phrase “of good reasons,” which modifies the subject.) “Wealth” is a
singular noun, so we need a singular verb; “are” is plural, so we have a subject-verb agreement error.

Step 2: Scan and Group the Answer Choices
(A), (B), and (C) retain the verb “are.” (D) and (E) both change the verb to “is.”

Step 3: Eliminate Choices Until Only One Remains
We know that “are” is incorrect, so we can eliminate (A), (B), and (C). Choice (E) changes “do aerobic
exercise regularly” to “do regular aerobic exercises,” which alters the meaning of the sentence in
an illogical way. Here we want the adverb “regularly,” which modifies how often a person should
engage in exercise, not the adjective “regular,” which modifies the noun “exercises,” indicating
that the exercises themselves should be “regular” or “normal.” Because the correct answer must
fix any existing errors without changing the meaning of the original sentence, (E) is incorrect, and
(D) is the correct answer.