South Corp.'s target capital structure is 50% debt, 10% preferred stock, and 40% common equity. If the before‐tax costs of debt, preferred stock, and common equity are 10%, 11%, and 14%, respectively, and the marginal tax rate is 40%, the WACC is closest to:
a) 9.3%
b) 9.7%
c) 10.3%
d) None of the above