4. (CPA adapted) Apex Corp. is considering the purchase of a machine costing $100,000. The machines expected useful life is five years. The estimated annual after-tax cash flow from operations is: $60,000 in year 1, $30,000 in year 2, $20,000 in year 3, $20,000 in year 4, and $20,000 in year 5. Assuming these cash flows will be received evenly during each year, the payback is:

a.2.50 years.

b.3.00 years.

c.3.33 years.

d.none of the above.