OE:
(1) Take a First Glance (5 seconds)
The beginning of each answer choice changes in structure from recommending to that recommend or to recommend. Something may be going on with the overall Sentence Structure or with Modifiers, so keep an eye on the core of the sentence (the main subject and verb) in the next step.
(2) Read for Meaning
The portion after the comma (overreliance … level) is quite dense. The first-glance clue to pay attention to sentence structure is going to be useful; try to strip this complicated sentence down to its core.
Mentally put the modifiers in brackets:
“overreliance [on marketing websites] [recommending that people focus primarily on counting calories] diminish their ability to achieve a certain weight loss or maintain a desired weight level”
The subject is overreliance and the verb is diminish. The first is singular and the second is plural; this is a Subject-Verb Agreement mismatch. Since overreliance is not underlined, the verb must change to the singular form. Eliminate choice (A), then scan the answers to eliminate any others that make this same error.
(3) Find a Starting Point
Start with any difference that seems easiest to you, then move to the next easiest issue, and so on. Stop when you have one answer or you aren’t sure how to address the remaining differences. All errors for each choice are detailed in the next section.
(4) Eliminate (and Repeat)
(A) The singular subject overreliance is incorrectly paired with the plural verb diminish.
(B) CORRECT. This choice correctly pairs the singular subject overreliance with the singular verb is diminishing. The middle part (a focus primarily on counting calories is diminishing people’s ability to …) may sound awkward, but there is nothing grammatically wrong with this construction—and awkwardness is not enough of a reason to eliminate an answer.
(C) The singular subject overreliance is incorrectly paired with the plural verb diminish. The parallel marker either X or Y is used correctly.
(D) The singular subject overreliance is incorrectly paired with the plural verb are diminishing. The parallel marker either X or Y is used correctly. Split infinitives, such as to either achieve, are no longer considered incorrect on the GMAT.
(E) This choice correctly pairs the singular subject overreliance with the singular verb is diminishing. However, the opening structure to recommend introduces an illogical meaning. Think of this structure as implying a purposeful action: She created a website (in order) to promote her new book. She created it for this purpose. But this choice illogically implies that the overreliance occurs in order to recommend a certain course of action. In fact, it was the websites that were created to recommend a certain course of action.