Verbal | DESPITE/ALTHOUGH

I have a question,

In OG17 Q#287 Choice C "Although observed..........., the discovery of...." --> this answer is wrong because of displacement of modifier. (Given by OA "discover" is not doing the "observe")

Well, I understand the explanation by OA but doesn't "Although it was raining, we went to the movies." violates the modifier rule presented by OA? or just Choice C is grammatically correct but the meaning?

Please help!! I am so confused!

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