GMAT Sentence Correction (SC) | Re: More than 300 rivers drain into Siberia's Lake Baikal, which

I think it is hard to know why B is wrong. I will try. all of you, pls, join discussion

the girl with red hat is my friend
with red hat, the girl is my friend

the first is right, "with..." phrase works as adjective.
the second is wrong because "with..." phrase works as adverb and shows the method of main clause. it is not logic because the girl is my friend by means of a red hat.

our choice B is similar. so, B is wrong.

takeaway
in the pattern
with+noun+comma+main clause
with