According to CAPM, which of the following are true under an efficient market? Pick all that apply.

a. Alpha is always 0 for all stocks

b. Alpha is positive only for very risky stocks

c. Only professional money managers can achieve a Sharpe ratio higher than the markets

d. No one can achieve a Sharpe ratio higher than the markets

e. Everyone will optimally invest in the market portfolio for the risky portion of their complete portfolio

f. The only way to earn higher returns than the market is to invest in stocks with high firm-specific risk

g. The only way to earn higher returns than the market is to increase the beta of your portfolio