If the after tax cost of debt is less than the cost of equity in a firm, which of the following relationships must be true? Assuming the has no preferred stock.

A) After-tax Cost of Debt < Cost of Equity = WACC

B) After-tax Cost of Debt < WACC < Cost of Equity

C) WACC = After-tax Cost of Debt < Cost of equity

D) After-tax Cost of Debt < Cost of Equity < WACC

E) WACC < After-tax Cost of Debt < Cost of Equity