A question about modifier and parallel (from OG Verbal)

[w.melindahere]

It from Verbal SC 27:

27. Obtaining an investment-grade rating will keep the county's future borrowing costs low, protect its already-tattered image, and increase its ability to buy bond insurance.

(A) Obtaining an investment-grade rating will keep the county's future borrowing costs low, protect
(B) To obtain an investment-grade rating will keep the county's future borrowing costs low, and protect
(C) Having obtained an investment-grade rating will, in keeping the county's future borrowing costs low, protect
(D) To obtain an investment-grade rating would keep the county's future borrowing costs low, protecting
(E) Obtaining an investment-grade rating, keeping the county's borrowing costs low, would be protecting

OA: A

the explanation of D: The faulty parallelism is confusing; PROTECTING introduces an adjective phrase describing the subject of the sentence, but this makes INCREASE into a verb with no subject.

I don't understand 'this makes increse into a verb with no subject'. Does it because the protecting makes the phrase become a modifier thus interrupt the parallel?

Please help me, thanks so much!

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Hi w.melindahere,

This SC is built around a 3-item List, so we need to follow Parallelism rules.

The third "item" in this List involves the word "increase", so we have to make sure that the other 2 items match the verb format.

According to the answer choices, the second item is either "protect" or "protecting." To be parallel, we need it to be "protect." (and not "and protect") Eliminate B, D and E.

Among the remaining answers, the first item is either "keep" or "keeping"; to be parallel, it must be "keep." Eliminate C.

Final Answer: A

As to why answer choice D is incorrect, the word "and" completes the 3-item list in the correct answer, but in answer D creates a new clause that has no subject/noun for the verb "increase."

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