Interwood Furniture initially had a capital structure consisting solely of equity. The risk free rate is 5% whereas the expected return on the market is 20%. The beta of the firm is 0.9. Gridline then changed its capital structure to consist of 30% debt. The corporate tax rate is 20%. What is the firms weighted average cost of capital with the new capital structure?

A. 17.39%
B. 18.5%
C. 20%
D. We would need to know the expected return on debt to calculate the firms weighted average cost of capital