A、Booking a theatre ticket. B、Reserving a room. C、Booking an air ticket. D、Reserving a seat. C该题为文章主旨题，根据文中开头提示信息“Will you book

M: Good morning. Wm you book a plane ticket to London for me?
W: Yes, sir. What time would you like to leave?
M: Next Tuesday, if possible.
W: That’ll be the 21st of December.
M: Yes, that’s right.
W: There are several flights available.
M: Would you check what flights ale available on the 21st of December?
W: All right. Let me check it over.
M: Morning flights will be perfect.
W: Yes, sir. There is a flight available on that day, at 10:00 a. m.
M: Fine. I’ll take that flight, then.
W: 10:00 a. m. I’ll fix your ticket.
M: When do I check in?
W: You must be there by 9:00 a. m.
M: Thank you.
Q9: What does the conversation talk about?