A firm should continue to invest in capital budgeting projects until its marginal cost of capital is:

A	equal to the net present value (NPV) of the last project purchased
B	equal to the internal rate of return (IRR) of the first project purchased
C	equal to the marginal return generated by the last project purchased
D	equal to the cash generated by the last project purchased
E	equal to the weighted average cost of all the projects purchased