Although just inside the orbit of Jupiter, amateur astronomers with go

B for me as well

(B) Although it is just inside the orbit of - it refers to Comet

The other choices except B is wrong because they do not modify comet. The true construction should be as Although just inside the orbit of Jupiter , the comet ..... However answer B fills the gap by introducing it . Since astronomers are plural and cannot be it there is no doubt that it clearly refers to comet. Clearly B

Who is inside the orbit of Jupiter? Astronomers? Absurd. All choices except B flaunt this fatal modification error. B is the only one, which by using a subordinate clause with a pronoun 'it', referring to the comet, amends this error.

since the opening clause modifies "comet", why is the "comet" not placed right after the comma ?

A. Although just inside the orbit of jupiter
This is a phrase and should modify the word immediately following comma.
(B) Although it is just inside the orbit of jupiter
This is a dependent clause..so need not modify the word following comma.
Eg: Although they were under the radar until recently, Joule Unlimited, the firm in Mass has two issued and at least three pending U.S. Patents.
(C) Just inside the orbit of
Same as A
(D) Orbiting just inside
Same as A
(E) Having orbited just inside
Same as A

You need something other than astronomers inside the orbit of Jupiter.
A,C,D and E don't have it.
The "it" in be is a saviour and hence is the right answer.!

Could I expect such SC problems in actual GMAT?
Such SC problems might test our knowledge but should not be scoring question.

uhhh another meaning game here.

the astronomers are not "inside the orbit of Jupiter". Instead, the comet is. Therefore, we should have a "it" precedent to refer to "comet". Otherwise, the meaning is changed.

I love this question because, at first sight, I interpreted the wrong meaning.
So before I propose the solution, would like to talk of the pitfalls/mistakes that one may do(As I did)::

Pitfalls:
1: Assuming the first phrase to be a modifier for "amateur astronaut": In the first go, it seems as if "just inside the ... of Jupiter" modifies the astronomer. Technically many are conditioned in such a manner. The moment we see a phrase, we presume it to be a modifier.

2: Wrong meaning: Some may confuse an astronomer for an astronaut and interpret that astronomer is orbiting Jupiter and while he/she does so notices the comet.

Solution
Kindly note the following pointers::
1: "Although" is conjunction, hence the first phrase should in fact be a clause. This means "ALTHOUGH" should be followed by SUBJECT + VERB. This can also be taken as a rule. I repeat, pls note:: For sentences containing "ALTHOUGH" immediately look for "sub+verb" after "although"

2: "ALTHOUGH" showcases a contrast and it generally does so by using a comma " , ". So if a sentence with "ALTHOUGH" has only one comma, it's highly probable that the two statements (before and after the comma)
in the sentence have to be contrasting statements. Also, the two statements have to be clauses each with a sub + verb.

Only one choice adds subject to the dependent clause. Hence, answer - B

Dear Experts,
I have read all the explanations but I can't understand why C is inferior to B. In my opinion, C can very well modify "Amateur Astronomers with good telescopes" and solve the problem of ever needing a pronoun.
Any thoughts?
Thanks

IanStewart, GMATNinja, egmat, MartyTargetTestPrep, KyleWiddison, zhanbo, DmitryFarber, GMATGuruNY

Here's the (C) version:

Just inside the orbit of Jupiter, amateur astronomers with good telescopes should be able to see the comet within the next few weeks.

We see that it conveys that amateur astronomers are "just inside the orbit of Jupiter."

At least in today's world, there's no way amateur astronomers would be "just inside the orbit of Jupiter," since amateur astronomers don't have space vehicles to get to that location. Thus, we can deem the meaning that amateur astronomers are just inside the orbit of Jupiter illogical and eliminate (C).

lol, Sorry, I updated the question to make it much more clear.
Well, can't "Just inside the orbit of Jupiter" modify "Amateur astronomers with good telescopes"?
As in, Amateur astronomers with good telescopes should be able to see the comet "Just inside the orbit of Jupiter".
This does make sense now? doesn't it?

Hello 0Lucky0,

We hope this finds you well.

To answer your query, in the sentence formed by Option C "Just inside the orbit of Jupiter" modifies "amateur astronomers"; this implies that the astronomers are orbiting Jupiter; although this may not technically be entirely impossible, it is not a logical interpretation of this sentence.

We hope this helps.
All the best!
Experts' Global Team

sorry, I updated the question to make it much more clear.
Well, can't "Just inside the orbit of Jupiter" modify "Amateur astronomers with good telescopes"?
As in, Amateur astronomers with good telescopes should be able to see the comet "Just inside the orbit of Jupiter".
This does make sense now? doesn't it?

Hello 0Lucky0,

We hope this finds you well.

To answer your query, "Just inside the orbit of Jupiter" cannot modify "comet"; in a “phrase + comma + noun” construction, the phrase must correctly modify the noun; this is one of the most frequently tested concepts on GMAT sentence correction.

We hope this helps.
All the best!
Experts' Global Team

Amateur astronomers cannot be just inside/outside/around the orbit. The GMAT Guru - GMATNinja - suggests that one must always be very careful and literal with the meaning in such modifiers questions. If the question had instead said Astronomers in rockets are able to orbit around Jupiter it would make sense for the opening modifier here to modify the astronomers, however, astronomers with telescopes leaves a dangling meaning behind. Are these astronomers using telescope from earth because if they are then there is no way these guys can orbit around Jupiter or are they using this telescope while they are in their rockets because in this case they may be able to orbit around a planet.
Hence, in my opinion there is ambiguity in this question around who's doing what. When we add the "it" - the pronoun directly refers to the comet and gives a clearer and more readily believable noun that may be doing the orbiting.