Hayden Company is considering the acquisition of a machine that costs $447,000. The machine is expected to have a useful life of six years, a negligible residual value, an annual net cash flow of $98,000, and annual operating income of $83,300. What is the estimated cash payback period for the machine (round to one decimal points)? a. 1.2 years b. 6.5 years c. 5.4 years d. 4.6 years