Hey daagh, actually there is a difference between "that of Japan" and "Japan's" here. We're making a comparison (X is larger than Y). The comparable elements are "its military" and "Japan's military," so we want them to have the same structure (possessive + noun). Since the second possessive "Japan's" can legally imply a repeated noun, this is OK. However, "its military" and "that of Japan" is a mismatch - it's unclear what we're comparing. So D is the correct answer.
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I see what you mean, here is some further explanation:

When the GMAT first says "its military" and then says "that of Japan," it's not immediately clear to me that they are making a comparison because those two noun phrases are not in the same format. Of course in real life I understand that we are comparing militaries, so the meaning is clear, but the structure is a problem.

However, when the GMAT says "its military" and then says "Japan's," it's clear that these two things are comparable. Even though the word "military" does not appear the second time, it's legal to use possessives to imply a noun that appeared earlier in the sentence. For example:

I like Sally's pies more than Rachel's.

This is a legal sentence. It implies the following:

I like Sally's pies more than Rachel's pies.

Hope that clears things up!
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appreciate your quick reply.

But can you help me with my doubt - i just rejected A,D and E as it contains "its" which is a possessive pronoun and as per my understanding, possessive pronoun refers to only possessive noun.

The original statement has a huge flaw which is comparing a military to a country, so that knocks out A and B.

The possessive "their" must be singular, because the United States is singular. This is reinforced by the fact that the verb outside the underlined portion is the singular "shoulders", so B (again) and C are eliminated.

We're down to D and E. E is incorrect twice, once for using the plural "those" when referring to its military, and second for the timeline of "has been larger..." not working with the present tense used outside of the underlined portion.

The answer is indeed D, and it's fairly obvious from eliminating clearly incorrect answer choices. I can understand the confusion on "its", but all the other answer choices must be eliminated (often twice) for egregious errors. I don't see this question as 700+.

Hope this helps!
-Ron
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The original sentence contains a faulty comparison: it compares the military of the
United States to Japan, rather than to Japan’s military.
(A) This choice is incorrect as it repeats the original sentence.
(B) This choice repeats the comparison error in the original sentence. Additionally,
this choice creates a pronoun error by using the plural pronoun “their” to refer to the
singular “United States.”
(C) This choice corrects the comparison error by comparing the military of the United
States to “that” of Japan. However, this choice includes a pronoun error by using the
plural pronoun “their” to refer to the singular “United States.”
(D) CORRECT. This choice correctly compares the military of the United States to
“Japan’s”; although “military” is not explicitly stated, the possessive form implies that it
refers to Japan’s military. Additionally, the singular pronoun “its” correctly refers to the
singular “United States.”
(E) This choice unnecessarily shifts to the present perfect tense “has been
larger,” which is not parallel with the present tense verb “shoulders” in the main
clause of the sentence. Furthermore, a military is a singular entity, whereas “those of
Japan” incorrectly refer to something plural.
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The possessive 'Japan's' , standing for Japan's military' is used to parallel the other possessive 'its'
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Because its military is larger and more technologically sophisticated than Japan, the United States shoulders much of the burden for patrolling and protecting the shipping lanes of the West Pacific.

D. its military is larger and more technologically sophisticated than Japan’s -

F. its military is larger and more technologically sophisticated than that of Japan -

1. In options D and F(created by replacing the pronoun 'their' to 'its' in option C), is option D better than option F?

2. In my opinion, both options D and F seem correct since the pronoun "that" in option F can refer to the noun military, but MGMAT instructor in the above post has stated otherwise.

AjiteshArun , GMATNinja , MagooshExpert , GMATGuruNY , VeritasPrepBrian , MartyMurray , DmitryFarber , daagh , generis , other experts - please enlighten
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