An investor can design a risky portfolio based on two stocks, A and B. The standard deviation of return on stock A is 20%, while the standard deviation on stock B is 15%. The correlation coefficient between the returns on A and B is 0%. The rate of return for stocks A and B is 20% and 10% respectively. The standard deviation of return on the minimum-variance portfolio is ___________.

A. 0%

B. 6%

C. 12%

D. 17%