Choose the correct answer$($s$)$

$(1)$ In the formula of WACC, we can estimate the return of debt r$($D$)$ by taking the total interest payment divide for the total outstanding debt

$(2)$ In the formula of WACC, we can estimate the return of equity by using CAPM for listed firm

$(3)$ In the formula of WACC, if the firm is private $($not listed$)$ obtaining r$($E$)$ return of equity will be more challenge because the beta is not available

$(4)$ In the formula of WACC, weight of equity, called w$($e$)=$ E$/($D$+$E$)$ where E is book value of equity and D is book value of debt

Question $13$