A company is considering purchasing a machine that costs $520000 and is estimated to have no salvage value at the end of its 8-year useful life. If the machine is purchased, annual revenues are expected to be $210000 and annual operating expenses exclusive of depreciation expense are expected to be $40000. The straight-line method of depreciation would be used. The cash payback period on the machine is

8.0 years.

4.1 years.

3.1 years.

2.0 years.