Colonna & Co can raise debt at a rate of 8 percent and its cost of equity and cost of preferred are 10% and 9% respectively. The tax rate is 40%. The company's capital structure consists of 50% equity, 40% debt and 10% preferred respectively. What is the company's WACC? O a. 5.90% O b.7.82% C. 4.15% O d. 9.00% O e. 9.10%