The answer is c

My explanation
A D and E are clearly out

Between b and c, b is wordy and the the part "senior citizen living longer by changing" is not correct

Love the question (Added just 1 Kudo , Wish GM Club had option to add a few more ) though got it wrong initially could identify my mistake.

The consultant team advised the insurance company that, in order to remain profitable through the upcoming decade, it had to -

1. diversify its long-term equity holdings,
2. streamline its now labyrinthine claims processing systems,
3. and to balance the added liability of senior citizens' living longer by changing its premium structure.

Diversify , Streamline and Balance is the correct gramatical form. - So options A, D & E can be eliminated.


A) and to balance the added liability of senior citizens living longer by changing - Incorrect

B) and balance the addition of liability with senior citizens living longer by changing - Incorrect

C) and balance the added liability of senior citizens living longer with changes to - Seems Correct.

The consultant team advised the insurance company that, in order to remain profitable through the upcoming decade, it had to

1. diversify its long-term equity holdings,
2. streamline its now labyrinthine claims processing systems, and
3. balance the added liability of senior citizens living longer with changes to its premium structure.

D) balancing the added liability with senior citizens living longer to change - Incorrect

E) thereby balancing the addition of liability with senior citizens living longer with changes to - Incorrect

Hence I fully support the OA (C).

PS : Indeed a wondurful question
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Magoosh Official Explanation:

Split #1: parallelism! We have three verbs, in the infinitive form, in parallel. We have two options: we could have the word "to" repeated in all three cases, or we could say the word "to" once at the beginning, and have it apply equally to all three terms:

option #1: "to diversify …, to streamline …, and to balance …"

option #2: "to diversify …, streamline …, and balance …"

Notice, the word "streamline" in the non-underlined portion does not have the word "to" in front of it: therefore, option #1 is impossible in this sentence, so we have to choose option #2. Having the "to" in front "balance", as in (A), is incorrect. Choices (D) & (E) have the participle "balancing", which completely violates the parallelism, so these are incorrect as well. Only (B) & (C) complete the parallelism correctly.

Split #2: the correct idiom is "balance X with Y." Here, we want to balance "liability" with "changes", so the preposition directly in front of the word "changes" should be the word "with." Only (C) & (E) have this correct.

Split #3: the phrasing "added liability" is certainly more concise than "the addition of liability", and arguable the latter changes the meaning slightly as well. For both reasons, we have to reject the latter, which appears in (B) & (E): those are incorrect.

The only answer that is both grammatically and idiomatically correct is (C).
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Hi,
Parallelism error: in the given sentence, there are two options to follow for a parallel structure: to diversify...., to streamline...., and to balance.... OR
diversify....,streamline....., and balance....
Since streamline part is in non underlined portion, we have to look for an answer choice that provides the second structure.
This brings us to option B & C.

here ..living longer....is an ing modifier used to modify its closest noun,senior citizen.

B. and balance the addition of liability with senior citizens living longer by changing: Here, use of complex gerund phrase, the addition of liability, is unnecessary. Use of with is incorrect. with senior citizens would mean to "use"(i dont know what would express the correct intention here) to balance the liability. According to sentence, senior citizens are the liability here.

C. and balance the added liability of senior citizens living longer with changes to: corrects all the issues presented and is indeed the right choice.
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