the problem with sentence #3 is that it's basically unreadable.
your underlying thought process is on point, in the sense that the following sentences are essentially identical in meaning:
With all the noise in here, I can't focus on my work.
I can't focus on my work with all the noise in here.
the main reason why the second version is workable, though, is its brevity. it's readable because it's short.
if the sentence is substantially longer—as is the case here—then the same type of thing becomes an unreadable mess of words, with no punctuation to save it.
needless to say, this is a style issue, and style issues aren't tested on this exam.
so—as in 99.9% of all cases with "user edits"—the answer is "#3 isn't really ok, but you don't need to worry about the reasons why."