A firm is evaluating two projects. Project A needs an investment of $18,000 and yields $6,000 annually for four years. Project B requires $22,000 with returns of $7,000 annually for four years. (a) Calculate the payback period for both projects. (b) Determine the NPV at a discount rate of 11%. (c) Compute the IRR for each project. (d) Discuss which project should be chosen if the firm can only select one.