15. Ninacent Corporation has a target capital structure of 70 percent common stock, 5 percent preferred stock, and 25 percent debt. Its costs of equit is 11 percent, the ost of preferred stock is 5 percent, and the pretax cost of debt is 6 percent. The relevant tax rate is 23 percent. What is the company's WACC? A. 8.15% B. 9.11% C. 10.25% 11.47%