AS PER KAPLAN:Read the Original Sentence Carefully, Looking for Errors:
The clause after the semicolon begins with the pronoun "this," but there is no singular noun for "this" to refer to. The author means that the "other avenues" include cutting executives' salaries. If a pronoun is used, it must be plural. Also, "cutting the salaries of executives" is wordier than it needs to be, since the possessive executives' could be used instead of the prepositional phrase "of executives."
Scan and Group the Answer Choices:
At first, you might group according to "unless" versus "without." However, as either of these could be correct, look for another way to group the answer choices. Since the pronoun after the semicolon is incorrect in the original sentence, this is a logical place to look for differences in the answer choices. There is lots of variety to choose from: (A) uses "this includes," (B) and (E) use "including," (C) uses "which would include," and (D) uses "these include."
Eliminate Wrong Answer Choices:
As discussed, the original sentence uses the incorrect singular pronoun "this" to refer to "avenues," so eliminate (A).
(C) changes the meaning of the sentence slightly by introducing the subjunctive mood with "would." The original sentence simply states that an option is to cut salaries. Also, (C) adds even more words to the awkward construction: "the cutting of salaries of the executives." Eliminate (C).
(D) replaces the words "this includes" with "these include." With this change, it fixes the pronoun agreement error. However, "the cutting of salaries of the executives" is still awkward. If a more concise and correct answer choice is available, choose it instead.
(B) and (E) get rid of the pronoun altogether by changing "include(s)" to "including," which now introduces a modifying phrase. (E), however, does not form a complete sentence when read into the original. The conjunction "unless" must introduce a clause that has a subject and verb, but there is neither here. Eliminate (E).
(B) corrects the pronoun problem by changing "this includes" to "including." It also makes the end of the sentence more efficient by changing the longer phrase "the salaries of executives" to the less wordy "executives' salaries." (B) is the correct answer.
TAKEAWAY: "This" must refer unambiguously to a singular noun.