Debreu Beverages has an optimal capital structure that is 70% common equity, 10% preferred stock, and 20% debt. Debreu's pretax cost of equity is 9%. Its pretax cost of preferred equity is 7%, and its pretax cost of debt is also 5%. If the corporate tax rate is 21%, what is the weighted average cost of capital?

7.79%

8%

8.74%

5.2%