I see your point and I agree _______ your proposal.

i answered with

study guide says to

WHY?????

2 answers

I guess it could be "to," but "with" is the more widely used and accepted.

=)
Further thoughts!

If you agree with someone, then you both have the same idea -- or the other person proposes something and you realize you are of the same mind.

If you agree to something, then something is proposed, and you agree to do it or to go along with it.