An investor can design a risky portfolio based on two stocks, A and B. Stock A has an expected return of 15% and a standard deviation of return of 29%. Stock B has an expected return of 10% and a standard deviation of return of 14%. The correlation coefficient between the returns of A and B is .5. The risk-free rate of return is 5%. The proportion of the optimal risky portfolio that should be invested in stock B is approximately O 30% O 48% O 52% O 70%