Rogers' Rotors has debt with a market value of $250,000, preferred stock with a market value of $50,000, and common stock with a market value of $700,000. If debt has a before-tax cost of 7%, preferred stock a cost of 9%, common stock a cost of 9.95%, and the firm has a tax rate of 30%, what is the WACC?

a. 8.64% b. 9.12%

c. 9.33% d. 10.88%