a$.$ If a project's NPV is greater than zero, then its IRR must be less than the cost of capital.

b$.$ The NPVs of relatively risky projects should be found using relatively low costs of capital.

c$.$ A project's NPV is generally found by compounding the cash inflows at the cost of capital to find the terminal value $($TV$),$ then discounting the TV at the IRR to find its PV$.$

d$.$ The higher the cost of capital used to calculate the NPV$,$ the lower the calculated NPV will be$.$

e$.$ If a project's NPV is greater than zero, then its IRR must be less than zero.