What Do the Two Terms R and K Represent in the IRR

Multiple Choice

What do the two terms r and k represent in the IRR rule k c r Accept?

A) k = net present value; r = discounted cash flow
B) k = discounted cash flow; r = net present value
C) k = internal rate of return; r = opportunity cost of capital
D) k = opportunity cost of capital; r = internal rate of return