Suppose that the expected return on the market portfolio ( Rm) is 12.3%. The Goldman Sachs Group's stock has a beta of 1.36. The expected return of the stock based on the CAPM is 15%. What is the risk-free rate? a) Between 0\% to 2.5% b) Between 2.51\% to 4% c) Between 4.01% to 6.5% d) More than 6.5\%