Explanation
Creating a filter: the original sentence is defective.
Namely, the portion before the dash gives us the subject of a sentence, "inflammation,"
and that subject never receives a grammatical predicate after the dash, because
a new grammatical subject is introduced with "it." So (A) is out. We need a
complete clause with subject and verb prior to the dash, not a hanging
grammatical subject.
Applying the filter: (C) and (E) are both hanging
subjects, so we're down to (B) and (D).
Finding objective defects: plugging (B) into the original
sentence sounds good. Plugging in (D) sounds wrong. The reason is that, since
there is no conjunction after the dashes and the clause after the dashes is an
independent clause, the clause before the dashes must be dependent. The word
"although" does the trick to make (B) dependent. The correct answer is (B).
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