You were hired as a consultant to Giambono Company, whose target capital structure is 40% debt, 15% preferred, and 45% common equity. The after-tax cost of debt is 6.00%, the cost of preferred is 7.50%, and the cost of retained earnings is 12.00%. The firm will not be issuing any new stock. What is its WACC?

a. 6.96% b. 6.69% c. 7.59% d. 7.68% e. 8.93%