In Calculating the NPV Using the Flow-To-Equity Approach the Discount

In calculating the NPV using the flow-to-equity approach the discount rate is the:

A) all equity cost of capital.
B) cost of equity for the levered firm.
C) all equity cost of capital minus the weighted average cost of debt.
D) weighted average cost of capital.
E) all equity cost of capital plus the weighted average cost of debt.