Question 7 1 pts 7. Boeing's cost of retained earnings is 10%, cost of preferred stock is 41% and its cost of debt is 4%. The optimal capital structure is 30% common stock, 35% preferred stock and 35% of debt. The firm will not be issuing any new stock and the marginal tax rate is 35%. What is the weighted average cost of capital for Boeing? 18.75% 18.26% 17 34% 19 54% 16.98%