单项选择题

M: I sent a letter to make a reservation for a single room a few days ago.
W: I’m sorry, but your request arrived too late. There are some conferences in town this week and we’re full up.
Q: Why couldn’t the man book a room as he wished?()

A.All rooms are taken.
B.There is just a single room.
C.There are only double rooms.
D.Many spare rooms are available.