Hazard Company is considering the acquisition of a machine that costs $525,000. The machine is expected to have a useful life of 6 years, a negligible residual value, an annual cash flow of $150,000, and annual operating income of $87,500. What is the estimated cash payback period for the machine? a. 3 years b. 5 years c. 3.5 years d. 4.3 years