A piece of equipment costs $31,000, and is expected to generate $8,600 of annual cash revenues and $1,900 of annual cash expenses. The disposal value at the end of the estimated 9-year life is $2,000. Ignoring income taxes, the payback period is:

3.60 years.

4.33 years.

4.63 years.

6.30 years.

None of these.