A firm wants to create a WACC of 10.4 percent. The firm's cost of equity is 14.5 percent and its pretax cost of debt is 8.5 percent. The tax rate is 34 percent. What does the debt-equity ratio need to be for the firm to achieve its target WACC?

a) 0.12 b) 0.98 c) 0.7 d) 0.86 e) 0.62

Please explain with as much detail as possible