听力原文：W: Look, Mr. Harris. This is the Great Pyramid.
M: Oh, yes...it looks very high!
W: It's about 137 meters high.
M: How long are the sides？
W: They're 230 meters.
M: It's incredible! Can we go inside？
W: I'm sorry, Mr. Harris. It's under repair these days.
M: What a pity!
(18)

A. 137 meters.
B. 230 meters.
C. 173 meters.
D. 213 meters.