Chapter 7 4. An investor can design a risky portfolio based on two stocks, A and B. Stock A has an expected return of 6% and a standard deviation of return of 10%. Stock B has an expected return of 12% and a standard deviation of return of 20%. The correlation coefficient between the returns ofA and B is 15%. The risk-free rate of return is 4%. Wha invested in stock A? t is the proportion of the optimal risky portfolio that should be a. b. What is the expected return on the optimal risky portfolio? c. What is the standard deviation of return on the optimal risky portfolio