9. You were hired as a consultant to Keys Company, and you were provided with the following data: Target capital structure: 40% debt, 10% preferred, and 50% common stock equity. The after-tax cost of debt is 4.00%, the cost of preferred is 7.50%, and the cost of common stock equity is 11.50%. What is the firm's WACC? a. 7.73% b.7.94% c. 8.10% d. 8.32%