Wonka Industries has a target capital structure of 35% debt, 10% preferred stock, and 55% common equity. The firm's pretax cost of debt is 6.50%, its pretax cost of preferred stock is 6.00%, its cost of equity is 10.50%, and its tax rate is 25%. What is the firm's WACC? O a. 9.37% Ob. 6.97% O c. 8.08% O d. 6.73% Oe. 6.11%