6. Nagel Equipment has a beta of 0.64 and an expected dividend growth rate of 3.00% per year. The T-bill rate is 4.00%, and the T-bond rate is 5.20%. The annual return on the stock market during the past 4 years was 10.25%. Investors expect the average annual future return on the market to be 13.70%. Using the SML, what is the firm's required rate of return? Do not round your intermediate calculations.

a. 10.64% b. 8.77% c. 8.43% d. 13.64% e. 10.21%