return for security i and R is the market's excess return The risk-free rate is 3% Suppose also that there are where Ri is the excess three securities A B, and C, characterized by the following data: Security 64 ECR) (e) 0.6 8% 21% 8 0.8 10 7 C1.0 12 16 a. If ?,-17%, calculate the variance of returns of securities A and C Variance Security A Security B Security C