Which of the Following Is True About the Security Market

Which of the following is true about the Security Market Line (SML) ? The SML:

A) Expresses a relationship between expected returns and systematic (non-diversifiable) risk.
B) Expresses the equilibrium relationship between expected returns and risk for all stocks.
C) Expresses the long-run average return.
D) Is a function of beta.
E) All of the above are true.