Heather Company is considering the acquisition of a machine that costs $360,000. The machine is expected to have a useful life of 6 years, a negligible residual value, an annual cash flow of $120,000, and annual operating income of $83,721. What is the estimated cash payback period for the machine? A. 5 years B. 2.5 years C. 4.3 years or D. 3 years