Procurement - PMP question

Your subcontractor delivered building raw material 3 days late, To bring some degree of satisfaction he reduced its cost by 5%. This offer is an example of

A. Compromise
B. Collaborate
C. Smoothing
D. Forcing

I selected answer A, but it's saying the answer is B (Collaborate).

Please clarify on this.

Correct answer is C. The subcontractor is trying to makeup for being late. Because the problem has already occured the only thing he can do is try to make concessions by offering a discount. There is not enough information but this could be a contract breach.

Answer A is not right because the seller is still getting his money just 5% less.

Answer B is not right because Collabrate means to solve a problem, no problem was solved here.

Answer D is not right because no one is forcing anything.

I vote for C

I agree with "Vote C", but not agree withe reason why not "A". It would have been "A" if there were a conversation/complaint prior to this offer. Am I right?