An investor can design a risky portfolio based on two stocks, A and B. Stock A has an expected return of 21% and a standard deviation of return of 39%. Stock B has an expected return of 14% and a standard deviation of return of 20%. The correlation coefficient between the returns of A and B is 0.4. The risk-free rate of return is 5%. The expected return on the optimal risky portfolio is approximately __________.

A. 10%

B. 20%

C. 12%

D. 16%

E. 14%