What is the payback period for a project with an initial investment of $180000 that provides an annual cash inflow of $40000 for the first three years and $25000 per year for years four and five, and $50,000 per year for years six through eight___?

a 5.8 yrs

b. 5.2 yrs

c. 5.4 yrs

d. 5.59 yrs