A firm has a target capital structure with 60% of debt (the pre-tax cost of debt is 10%), 30% of common equity (the cost of common equity is 15%), and 10% of preferred stock (the cost of preferred stock is 12%). If we assume this firm has a 30% corporate tax rate. Whats the firms WACC?

A) 8.5%

B) 9.3%

C) 9.9%

D) 11.7%