What is the weighted-average cost of capital for a firm with the following sources of funds and corresponding required rates of return: $15 million common stock at 15%, $5 million preferred stock at 9%, and $10 million debt at 6%. All amounts are listed at market values and the firm's tax rate is 35%.

A. 9.0%

B. 10.3%

C. 12.1%

D. 13.5%

E. 14.4%

*show work please