听力原文：W: I suppose the traffic in the city is heavy at the end of the day when people are leaving the city for homes.
M: Yes. The worst time is between six and seven. It sometimes takes me forty minutes to drive home. That's twice the time it does when there isn't much traffic.
Q: How long does it take the man to drive from the city to his home when there isn't much traffic？
(13)

A. Forty minutes.
B. Twenty minutes.
C. Eighty minutes.
D. Seventy minutes.