Your A, B, and C are all correct. " and the verb should agree with what follows. When used another way, such as "I don't think much is going to come out of this meeting" or "Not much is happening" or "Much is still to be learned about how great white sharks navigate the deep ocean waters" -- then much does take the singular.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.