Hayden Company is considering the acquisition of a machine that costs $$525,000.$ The machine is expected to have a useful life of $6$ years, a negligible residual value, an annual net cash inflow of $$94,000,$ and annual operating income of $$79,900.$ The estimated cash payback period for the machine is $($round to one decimal place$)$

$$ a$.6\mathrm{.}6$ years

b$.5\mathrm{.}6$ years

c$.7\mathrm{.}7$ years

d$.1\mathrm{.}2$ years