If an asset's expected return is less than its required return, rational investors will ________.

A. sell the asset, which will drive the price down and cause the expected return to reach the level of the required return

B. buy the asset, since price is expected to increase

C. sell the asset, which will drive the price up and cause the expected return to reach the level of the required return

D. buy the asset, which will drive the price up and cause expected return to reach the level of the required return