Questions 17 ～ 20 are based on the following talk. You now have 20 seconds to read Questions 17 ～ 20.

"Big Top" is ______.

A．He would have liked to earn as much money as they did.
B．He was afraid of being compared unfavourably with them.
C．He did not think he could write about the same subjects.
D．He had a low opinion of the kind of books they wrote.

A．investors are not always rational
B．stock price reflects all available knowledge
C．a rational investor should be good in prediction of the market
D．because new information is unprediction it is hard for investors to be rational