V. Choose the letter A, B, C, or D to indicate the word or phrase that best completes each of the following exchanges.

1. Mat: "Thank you for taking the time to explain this to me." Tom:A. Well, I didn't have much else to do, so explaining this seemed like a way to pass the time. B. No problem at all, it's my pleasure to help you understand. C. I hope you're grateful for my effort in clarifying this. D. I’m not sure why you're trying, but here's the explanation anyway.