The Security Market Line (SML) provides the relationship between and required rate of return. Which of the following statements about the SML is most correct? The relevant risk is portfolio risk, which is measured by beta. The relevant risk is total risk, which is measured by standard deviation. The relevant risk is mutual risk, which is measured by coefficient of variation. The SML is an equation, but it cannot be graphed. The SML is a graphed line, but it cannot be expressed as an equation