Answer:
At the Internal Rate of Return (IRR).
Step-by-step explanation:
The Internal rate of return is the Interest rate that will make the Present Value of Cash Flows equal to the price or cost of the initial investment. This rate gives a Net Present Value of zero.
If at that rate both Project A and Project B give a Net Present Value of zero, you will be indifferent (the choice is the same irregardless of the alternative chosen).
Project that provide for a return greater than the Internal Rate of Return must be chosen.