Optima Industries is considering two new projects with the following net cash flows. The company's required rate of return on investments is 12%. Use appropriate factors from the tables provided.

Year	Project A	Project B
0	$(120,000)	$(90,000)
1	$30,000	$20,000
2	$40,000	$25,000
3	$50,000	$35,000
4	$60,000	$40,000

a. Compute the payback period for each project. Based on the payback period, which project is preferred?

b. Compute the net present value for each project. Based on net present value, which project is preferred?