consider two mutually exclusive projects A & B. If you subtract the cash flows of opportunity B from the cash flows of opportunity A, then you should:

1) take opportunty A if the regular IRR exceeds the cost of capital

2) take opportunity A if the incremental IRR exceeds the cost of capital

3) take opportunity B if the regular IRR exceeds the cost of capital

4) take opportunity B if the incremental IRR exceeds the cost of capital