Alpha Tech Corp. is evaluating two potential projects, both requiring an initial investment of $50,000. The after-tax cash inflows for each project are as follows:

Year	Cash Flows (Project A)	Cash Flows (Project B)
0	-50,000	-50,000
1	15,000	20,000
2	15,000	20,000
3	15,000	20,000
4	20,000	10,000

a. Calculate the payback period for Project A and Project B. b. Which project should Alpha Tech Corp. invest in if the cost of capital is 6%? Show the NPV calculations.