For the following set of cash flows, Year 0 Cash Flow -$7,900 5,600 5,700 3,100 2 3 a. What is the NPV at a discount rate of O percent? b. What is the NPV at a discount rate of 9 percent? c. What is the NPV at a discount rate of 23 percent? d. What is the NPV at a discount rate of 28 percent