Question $8$ Suppose that a firm's capital is composed of $30$ percent common equity and $70$ percent debt; no preferred stock is used. In addition, the before$-$tax cost of the debt is $10$ percent, the cost of the equity is $15$ percent, and the firm's marginal tax rate is $46$ percent. The firm's weighted average cost of capital is O $8\mathrm{.}28$ percent. O $12\mathrm{.}50$ percent. O $7\mathrm{.}72$ percent. O $11\mathrm{.}50$ percent. O $13\mathrm{.}50$ percent.