Which of the following formulas correctly represents WACC?

The formula for WACC (Weighted Average Cost of Capital) reflects the average rate of return that a company is expected to pay its security holders to finance its assets. In option C, the calculation correctly incorporates the proportion of equity and debt in the company's capital structure, multiplied by their respective costs.

This option explicitly recognizes the weighted nature of capital components, where the percentage of equity and debt is multiplied by their costs. Furthermore, the inclusion of the tax shield on debt (represented by "(1-T)") acknowledges that interest payments on debt are tax-deductible, ultimately affecting the firm's overall cost of capital. This consideration is crucial as it aligns with how businesses often evaluate their financing options.

The other options lack the proper structure to represent WACC accurately. They either misrepresent the relationship between equity and debt or ignore significant factors such as tax implications or correct weightings. Therefore, the formula in option C not only captures the components of WACC accurately but also reflects the financial principles governing corporate finance.