Stock A has an expected return of 12% and a beta of 1.2. Stock B has an expected return of 9% and a beta of 0.8. Both stocks have the same reward-to-risk ratio. What is the risk-free rate? (Please explain the calculation.)
a. 3.0%
b. 4.0%
c. 4.5%
d. 2.5%
e. 3.5%