I would go for C because of concision. I consider C to be much "cleaner" and concise. That Spends.

a- in its spending --> Wordy
b- insect known --> I would consider known insect as a much correct choice.
d- Mixture of A and B
e- that is known --> I would consider as any other known insect much concise.

I have used this elimination process, mainly because of concission. Any comments?

\(NAIL\) \(THE\) \(SENTENCE\) \(CORRECTION\) \(SECTION\)

After spending plenty of time in the Sentence Correction section, one thing I can assure each and every member is that the best technique to nail the SC section is to try and find out as many errors in an answer choice as possible. In general, if one observes he may find atleast 3 errors in all the incorrect answer choices. So the motive behind this topic is to destroy each Official question in SC.
By discussion we will equip ourselves with every weapon in order to conquer SC section.

Advantages of SC:
1) With sufficient skills, we CAN solve any SC question under a minute.
2) Finding all the errors while practicing can help us solve each SC question under a minute in real test.
3) No brain is needed. Just the application of rules.
4) Time saved in SC is the bonus for the rest of the verbal section.

NOTE: UNSOURCED QUESTIONS WILL IMMEDIATELY BE REMOVED AND 1000 SERIES IS PROHIBITED.

P.S. I am fed of the pathetic explanations of OG.
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On a glacier in the high Himalayas, a Japanese zoologist has found a species of midge that is unlike any other known insect in its spending its entire life cycle in the snow and ice of glacier.

a)that is unlike any other known insect in its spending
b)that is unlike any insect known as it spends
c)that, unlike any other known insect, spends
d)unlike any insect known as it spends
e)unlike any other insect that is known, spending

Meaning:
Sentence says that Japanese zoologist has found a species of midge, and this species is unlike any other species because it spends its entire life in snow.

a)The problem with original choice is that its spending its entire life cycle phrase can act as Noun Modifier modifying phrase "any other know insect" or can act as adverbial modifier modifying clause " How species of midge is different from other insects?". hence ambiguous.

b) it spends - it can serve as a referrent of Zoologist, since it is subjective pronoun can act in place of subjective "noun"

c) correct - ambiguity is removed.

d) has same error as that of b

e) changes meaning. presenting the result of an effect. Moreover, redundant construction

On a glacier in the high Himalayas, a Japanese zoologist has found a species of midge that is unlike any other known insect in its spending its entire life cycle in the snow and ice of glacier.

a) that is unlike any other known insect in its spending............its spending its lifecycle seems awkward with redundancy.
b) that is unlike any insect known as it spends................as it spends defines a reason for not being like others but it is not mentioned so.
c) that, unlike any other known insect, spends..........seems best and short.
d) unlike any insect known as it spends..............unlike seems to refer midge but needs a realtive pronoun to refer it.
e) unlike any other insect that is known, spending.................unlike spoils the dish again. Also spending suggests that Zoologist found midge while spending and again its life indicates that you are not getting the intended meaning.
Also that is known is redundant just like B instead of known insect.

Also any other vs any is one more criteria mentioned in below link.
https://www.youtube.com/watch?v=FUBR8P9AkH4

The conjunction "as" is used to mean "because". In options B and D the meaning conveyed is:

A Japanese zoologist has found a species of midge because the midge spends its entire life cycle in the snow and ice of glacier.
Cause: The midge spends its entire life cycle in the snow and ice of glacier.
Effect: A Japanese zoologist has found a species of midge

The above meaning is absurd.

GMATNinja, GMATNinjaTwo, DmitryFarber, Does comma in answer choice C been used correctly?
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Good question, ziyuen. And yes, the commas are completely fine. The phrase inside the commas is just setting up a comparison with the midge, and the commas help separate it from the rest of the sentence.

Consider the following:

Unlike any other known insect, midges live in glaciers.
Midges, unlike any other known insect, live in glaciers.

No problem with either of these, right? The comparison is correct, and in that second sentence, you clearly need the commas for separation. (C) is similar, expect that now the "unlike..." phrase is part of a modifier beginning with "that":



So the commas correctly separate the description from the rest of the clause. It would be muddier without the commas.

But for whatever it's worth: I can't really think of any GMAT SC questions that really test you on comma usage. Semicolons, perhaps -- but comma usage is never a deciding factor.

I hope this helps!
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OFFICIAL EXPLANTION:

Answer Explanation Close
Grammatical construction; Logical predication; Rhetorical construction

The sentence reports a zoologist’s discovery of a species of midge that is unique among all the insect species on earth. The sentence needs to clarify that the species discovered is being compared to other insects.

A. The phrase in its spending its is awkward and confusing because of the unnecessary repetition of its.
B. Without other to modify insect, the sentence excludes species of midge from the category insect where it logically belongs.
C. Correct. The qualified category other known insects is logically distinct from the noun midge, so the comparison makes sense.
D. The category insect must be qualified by the adjective other, as explained in C.
E. The phrase that is introduces unnecessary words to this version of the sentence. Because of its placement, the adjective phrase spending its entire life . . . seems at first to be describing the Japanese zoologist, not the midge.

The correct answer is C.