Assume that the % expected return for security A and the market M for a good, normal and bad economy (probabilities.3.4.3) are 20, 16, and 10 for A and 8,4, and 12 for M. Also assume that you invest 40% in A and 60% in M. Compute the standard deviation for A. O 15.4 O 3.90 O 3.32 0.-7.44