4. Consider the following cash flow profile and assume MARR is 10 percent/year. NCF 0 -$100 1 2 3 4 5 6 $25 $25 $25 $25 $25 $25 a. What does Descartes' rule of signs tell us about the IRR(s) of this project? b. What does Norstrom's criterion tell us about the IRR9s) of this project? c. Determine the IRR(s) for this project. d. Is this project economically attractive