A piece of equipment costs $30,000, and is expected to generate $8,500 of annual cash revenues and $1,500 of annual cash expenses. The disposal value at the end of the estimated 10-year life is $3,000. Ignoring income taxes, the payback period is:

3.53 years

3.86 years

4.29 years

6.98 years

some other period of time not noted