Hayden Company is considering the acquisition of a machine that costs $357,000. The machine is expected to have a useful life of 6 years, a negligible residual value, an annual net cash inflow of $80,000, and annual operating income of $68,000. The estimated cash payback period for the machine is (round to one decimal place) a. 1.2 years b. 5.3 years c. 4.5 years d. 6.4 years