What is the multiple rates of return problem?

Select one:

a. It makes it challenging to use the NPV since the value will be different depending on what discount rate is used.

b. It makes it challenging to rank projects using the NPV since the ranking may depend on what discount rate is used (i.e. at 6% A is better than B and at 8% B is better than A).

c. It makes it impossible to use the IRR when cashflows are not conventional because there may be more than one IRR solution.

d. It makes it impossible to rank mutually exclusive projects using the IRR because IRR rankings do not change when the discount rate changes.