Create a VBA function named WACC. This function will have 5 inputs. The market value of equity, the book value of debt, the cost of equity, the cost of debt, and the firms tax rate. This function will return the firms weighted average cost of capital. Using this function, compute the WACC of a firm with $50 billion in equity, $10 billion in debt, a cost of debt of 5%, a cost of equity of 13%, and tax rate of 21%.