You have a two-stock portfolio. One stock has an expected return of 12% and a standard deviation of 24%. The other has an expected return of 8% and a standard deviation of 20%. You invested in these stocks equally (50% of your investment went toward each of the two stocks). If the two stocks are negatively correlated, which one of the following is the most feasible standard deviation of the portfolio?

A)23%

B)22%

C)21%

D)not enough information to determine