Exercise 4_ch3_no7 (NPV, IRR, IRR crossover point): Your firm is considering two projects with the following cash flows: a.) If the appropriate discount rate is 12%, rank the two projects. b.) Which project is preferred if you rank by IRR? c.) Calculate the crossover rate, namely, the discount rate r at which the NPVs of both projects are equal. d.) Should you use NPV or IRR to choose between the two projects? Briefly discuss