Ninecent Corporation has a target capital structure of 75 percent common stock, 10 percent preferted stock, and 15 percent debt, its cost of equity is 9 percent, the cost of preferred stock is 5 percent, and the pretax cost of debt is 6 percent. The relevant tax rate is 21 percent. a. What is the company's WACC? Note: Do not round intermedlate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16. b. What is the oftertax cost of debt? Note: Do not round intermedlate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16