Which of the following statements is most correct?

A. If the NPV of a project is positive then the payback rule will always accept the project.

B. If the NPV of a project is negative then the profitability index will always be greater than one.

C. For projects in which the cash flows switch direction (i.e. from positive to negative or vice-versa) more than once, the NPV criteria may give multiple solutions.

D. For a project with conventional cash flows, the NPV, IRR, and PI rules are equally valid and give the same accept/reject decision.

E. If the PI of a project is greater than one, then the IRR will always be less than the required rate of return.