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.

F: Hello, China Travel Agency. Can I help you? ,M: Yes, I'd like to travel to London. So I want to make a reservation for me on May fourth. ,F: Just a moment, please. I'm sorry, but the flights are fully booked on that day. The next available flight is on May fifth. They have 2 flights: one at 9:30 AM and the other at 2:00 PM. Both flights have seats available.
(A) M: I didn't hear you. Please could you tell me again? (B) M: So, as a stewardess, you mean the flights are not fully booked on that day? (C) M: Really? As a booking clerk, you mean they have one flights: at 9:30 AM? (D) M: So, you mean as a customer, you mean the next available flight is on May third?
Output:
A