Like any star of similar mass would do, once the Sun has exhausted the hydrogen in its core, it expands into a red giant, eventually ejecting its outer envelope of gases to become a white dwarf.

(A) Same
(B) Like any star of similar mass, once the hydrgogen in the Sun's core is exhausted, then it expands into a red giant and eventually ejects
(C) As in the case of any star of similar mass, once the hydrogen in the Sun's core is exhausted, it will expand into a red giant, and eventually ejecting
(D) As any star of similar mass would, once the hydrogen in the Sun's core is exhausted it will expand into a red giant and will eventually eject
(E) As would be the case with any star of similar mass, once the Sun exhausts the hydrogen in its core, it will expand into a red giant and eventually eject

Please explain your answer.

E for me.

Sentence is making a projection. So, future tense is needed. A and B are out. The 'its' after the underlined portion should refer back to Sun and not SUn's core. C and D have 'Sun's Core' and 'it' cannot refer to a possessive.

I will go with E too

Givemeanid is correct about the 'possessive poison' (i.e., pronouns can't refer to a possessive noun) aspect. As always, though, this obscure fact isn't necessary to solve the problem: what's more important is to notice that, in choices C and D, "it" refers to "hydrogen" (the subject of the previous clause). This reference leads to the absurd idea that the _hydrogen_ will expand into a red giant AFTER IT'S ALL GONE. Choice C also exhibits a rather obvious parallelism defect, which also happens to be ungrammatical: "and eventually ejecting" not only fails to be parallel to "will expand," but is also, well, wrong.

Choice B is all kinds of wrong. Since "like any star of similar mass" doesn't have a subject, we need "the Sun" right after the comma (and it isn't there). Like choices C and D, this sentence mistakenly employs "it" to refer to hydrogen. And givemeanid has already pointed out the tense problem.

Thanks for the detailed explanation Ron, it helps!

Can I eliminate choice "A" on the basis that it is starting a clause with "like"----->"Like any star of similar mass would do".

It is wrong to use "like" to start a clause in place of "As" ?

Thanks

it is indeed wrong.

like is limited to introducing nouns (or their equivalents, such as pronouns and noun phrases). you are correct to assert that like cannot introduce clauses.

Hi,

Why does the sentence use "as would be the case..." instead of "as is the case..."?
Is it talking about a similar phenomenon/situation that happens to Sun?
How should I decide the proper tense in "as [be] the case..."?
Another similar question in GMATPrep: http://www.manhattangmat.com/forums/as-it-is-with-traditional-pharamacies-on-line-drugstores-t2420.html

anyone?

"As would be the case" is better than "as is the case" for this sentence because it refers to a hypothetical star of similar mass to the Sun's. If the sentence referred to a specific star to which this happened, then "as was the case" would be appropriate since the construction would refer to an actual event.