Thinking about the relationship between NPV and IRR, which one of these statements is ture

a. When NPV equals the required rate of return, IRR equals zero

b. When NPV equals zero, the required rate of return is greater than IRR

c. When IRR is greater than the required rate of return, NPV is less than zero.

d. When NPV equals IRR, the discount rate equals zero.

e. When IRR equals the required rate of return, the NPV equals zero.