I agree . . . . . . . . your wedding proposal.

A. with

B. to

C. in

D. of

Answer: Option B

Solution(By Examveda Team)

"I agree to your proposal" means that whatever you've proposed requires my involvement, and signals my acceptance of it. "I agree with your proposal" means that you've described your proposal to me (it may or may not actually involve me), and signals that I think it sounds like a good idea.