Hayden Company is considering the acquisition of a machine that costs $363,000. The machine is expected to have a useful life of 6 years, a negligible residual value, an annual net cash flow of $96,000, and annual operating income of $81,600. What is the estimated cash payback period for the machine (round to one decimal points)? 3 3.8 years b. 5.6 years C. 4.4 years d. 1.2 years