Ronnie's Comics has found that its cost of common equity capital is 15 percent and its cost of debt capital is 12 percent. If the firm is financed with $250,000,000 of common shares (market value. and $750,000,000 of debt, then what is the after-tax weighted average cost of capital for Ronnie's if it is subject to a 35 percent marginal tax rate?

a. 6.05%

b. 9.6%

c. 8.75%

d. 13.65%

Please show how its done by hand or calculator

DO NOT USE EXCEL PLEASE