You will be given a definition of a task first, then some input of the task.
In this task you are given a small conversation between two persons and 4 options on how the conversation should continue. Your job is to choose the most reasonable option. The conversation and the options are separated by a newline character. Each dialogue in the conversation are separated by a comma. F and M indicate female and male, respectively.

M: So, we're back in class at last. I didn't see you around this summer, Mary. Did you leave Beijing?
(A) F: Yes, I left Beijing during winter vocation. Do you need something to drink? I have some coffee in my apartment. (B) F: It is good to be back to classroom. Do you remember the teacher of our interest class we took together? (C) F: I didn't hear you. Please could you tell me again? (D) F: Yes, it is good to be back to classroom. Actually, I went to travel around, which was interesting but tiring.
Output:
D