单选题 What did Greenspan warn the investors about assets like stocks and houses?

A、 He warned them not to wait to buy stocks or houses.
B、 He warned them not to think the value of stocks or houses will rise permanently.
C、 He warned them that the stocks and houses should be priority.
D、 He warned them that the price of stocks and houses would decrease next year.

【正确答案】 B

【答案解析】[分析] 见文章第三段 Earlier，he had warned investors not to assume higher prices for assets such as stocks or houses were permanent，saying gains could disappear if the economy or investor sentiment turned。