听力原文： Mr. Smith was a wealthy industrialist, lint he was not satisfied with life. He did not sleep well and his food did not agree with him. This situation lasted for some time. Finally, after several nights, he decided to consult his doctor. The doctor advised a change of surroundings. "Go a-broad," he said. "But I'm not good at foreign language," said Mr. Smith. "It doesn't matter," said the doctor.
"It won't hurt you to talk a little less. Go on a voyage. Try to reduce your weight. Avoid rich food."
Mr. Smith went to Switzerland. He did not know French or German and had to communicate through gestures. He attended a physical training course. The instructor made him bend his knees, swing his arms, stretch his neck and shake his head rapidly. He had to lie on the ground and raise his right and left legs alternatively. After a time his muscles grew hard and firm. He forgot the financial-crisis and the importance of raising the level of production. He even began to notice individual trees and individual birds.
Finally he returned home. But unfortunately his improvement was only temporary. Soon he was a normal businessman again, worried about his property, his profits, his savings, his advancement in a technological society, and things in general.
What advice did the doctor give Mr. Smith？

A. To eat less.
B. To have more exercises.
C. To change his surroundings.
D. To forget about his business.