Hayden Company is considering the acquisition of a machine that costs $463,000. The machine is expected to have a useful life of six years, a negligible residual value, an annual net cash flow of $99,000, and annual operating income of $84,150. What is the estimated cash payback period for the machine (round to one decimal points)?

a.6.7 years

b.5.5 years

c.1.2 years

d.4.7 years