In the U.S. Army, individual squads are combined to form platoons of 1

I can help!

The clause that you are looking at does have a verb! In the clause, "consisting" is the verb in the clause.
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Kevin isn't "consisting" should be used with a helping verb to be used as a verb in the clause.

My apologies. I am totally wrong, and you are totally right. Usually we would need a helping verb. I did not look at the sentence close enough. Here "consisting" functions as a gerund, creating a modifying phrase that describes an aspect of the platoons. As such, no "be" verb is needed. Here is another example of using "consisting" like this:

"Brazilian officials announced the finished list of 83 on Tuesday, each consisting of a training centre with football pitches and a partner hotel." -Reuters
"The Arctic 30, consisting of 28 activists and two journalists, face up to seven years in prison on charges of hooliganism." -Salon

My apologies once again. I hope that this helps sort our the issue.
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A is not prefered though can be right in other questions because "which" is far from "platoon"
in C, "with+noun+noun modifier" should modify the main clause. but this modification is not logic here

B is good.

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Added the OA. It's B.
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Could anyone explain why option E is wrong ?

is it because of an independent clause and missing semi colon ?

Correct. E is a "run-on" sentence: Two Independent clauses, connected by just a comma.

p.s. Our book EducationAisle Sentence Correction Nirvana discusses run-on construct, its application and examples in significant detail. If you or someone is interested, PM me your email-id; I can mail the corresponding section.
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The structure for D is:

individual squads are combined to form platoons of 16 to 44 soldiers, and each platoon consisting of a lieutenant and an NCO (non-commissioned officer), who are first and second in command, respectively.

There is nothing parallel to consisting in the first half of the sentence. At the very least, the sentence should have been:

individual squads are combined to form platoons of 16 to 44 soldiers, and each platoon consists of a lieutenant and an NCO (non-commissioned officer), who are first and second in command, respectively.
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What's the difference between (A) and (B)?

Hello, lakshya14. I will admit that I took a minute (well, 58 seconds exactly) to tease out what separated the two contenders before I opted for (B). What separates the two? Clarity of meaning, the silver bullet of SC. Although people talk the way the original sentence is phrased, each of which can, at first glance, seem to refer to soldiers instead of the earlier platoons (even if I would expect whom instead of which to be used if such were the intended meaning). Look at the sentence again:

(A) In the U.S. Army, individual squads are combined to form platoons of 16 to 44 soldiers, each of which consists of a lieutenant and an NCO (non-commissioned officer), who are first and second in command, respectively.

(B) In the U.S. Army, individual squads are combined to form platoons of 16 to 44 soldiers, each platoon consisting of a lieutenant and an NCO (non-commissioned officer), who are first and second in command, respectively.

There is no question about what consists of a lieutenant and an NCO in (B). Clear and direct expression of meaning is preferred on the GMAT™, plain and simple. If there is any doubt between one answer choice like (A) and another like (B), play it safe and steer clear of the iffy one.

- Andrew
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