The answer is B: Ask what you can do to fix the problem.
In any form of communication between coworkers that addresses a given problem, the most successful interaction will be the one that seeks a way to solve the problem. Proposing a solution or being in a disposition to solve the problem —like in this case— will always be more efficient than any kind of excuse, justification or finger-pointing. Business relationships should always remain constructive for them to be successful.
