W: 796-3758.
M: Hello. James Clock speaking. May I have a word with Mary
W: I’ll just see if she’s in.
M: Right you are.
W: I’m afraid she’s not here.

Who answered the phone（）

A. how to 
B. how
C. what to
D. what

A. it protects him against the harmful rays from space
B. it provides sufficient light for plant growth
C. it supplies the heat necessary for human survival
D. it screens off the falling meteors