The risk-free rate is 5%. The expected market rate of return is 11%. If you expect stock X with a beta of 2.1 to offer a rate of return of 15%, you should

A. buy stock X because it is overpriced.

B. sell short stock X because it is overpriced.

C. sell short stock X because it is underpriced.

D. buy stock X because it is underpriced.

E. None of the options, as the stock is fairly priced.