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.

Example Input: F: Excuse me, could you tell me how to get to the Water Cube from here? ,M: You can take a bus or a taxi. But the traffic is very heavy at the moment. So you'd better take the subway.
(A) F: Thanks for the advice, I'm definitely going to take the subway. (B) F: I take the subway to school every day. (C) F: You mean I should take a bus? (D) F: I’m sorry, I don’t understand. Could you say it again?
Example Output: A

Example Input: F: What can I do for you? ,M: I want to check out these books. ,F: Your library card, please? Oh, you have late fees. It comes to $4. You have to pay it off before you can check out more books. ,M: OK, no problem.
(A) F: Sorry, our bookstore is closing now. (B) F: You can apply for a library card over there. (C) F: Just a minute! I do not quite follow what you are saying, would you mind repeating that? (D) F: Besides, may I see your ticket to the museum? I need to check it out.
Example Output: C

Example Input: M: I need to use the restroom, but the door is locked. No one is in there, because I already knocked on the door. Can you give me the key? ,F: Well, the restroom is for customers only. So you'll need to buy something.
(A) M: OK. I will buy something. (B) M: I’m sorry, I didn’t understand. Could you repeat a little louder, please? (C) M: OK. I'll look for the keys first. (D) M: OK. I am going to knock on the door first.
Example Output:
A