Assuming that markets are semistrong efficient,which of the following statements is correct?

A) All stocks should have the same expected return.
B) Past stock prices can be successfully used to forecast future stock returns.
C) Investors' most likely returns are those predicted by the SML, but one should not expect to do any better unless he or she has either good luck or access to information that is not publicly available.
D) Investors should expect to earn more than the returns that are predicted by the SML, because if they do not, they should not invest in the stock market.

If markets are semistrong efficient, all publicly available information including past stock prices, should be reflected in the current market price. Therefore, it is difficult to consistently beat the market using this information. According to the SML, an investor should expect to earn a return that compensates for the level of risk they are taking. Any returns earned above this level would be due to luck or access to private information. Therefore, the most likely returns for an investor are those predicted by the SML, but it is unlikely that they will consistently earn returns above this level without an information advantage. Option A and D are incorrect because not all stocks have the same expected return and investors should not expect to consistently earn returns above what is predicted by the SML. Option B is incorrect because past prices should already be reflected in the current price.