8. Payback Consider the following projects: Cash Flows (S) Project Co C C3 C4 A 1,000 +1,000 B 2,000 +1,000 +1,000 +4,000 +1,000 +1,000 C 3,000 +1,000 +1,000 0 +1,000 +1,000 a. If the opportunity cost of capital is 10%, which projects have a positive NPV? b. Calculate the payback period for each project