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:

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