Investment Z has an internal rate of return (IRR) of 16 percent. Investment X has an IRR of 15 percent. Both projects have a cost of capital of 13 percent. Which of the following statements is most correct?

a. Investments Z and investment X have a positive net present value (NPV).

b. Investment Z must have a higher NPV than Investment X.

c. If the cost of capital were less than 12 percent, Investment X would have a higher IRR than Investment Z.

d. Statements a and b are correct.

e. None of the statements above are correct.