If the efficient market hypothesis holds, what should an investor do whenever he or she finds that the required return of stock is less than the expected return of the stock? Select one: a. The investor should buy more of the stock, which will not affect the price of the stock but will increase the stocks return. b. The investor should sell the stock, which will drive the price down and increase the market return. c. The investor should buy more of the stock, which will drive the price and the return of the stock higher. d. The investor should sell the stock, which will cause the market to crash.