Macpherson Engineers is evaluating an investment proposal using the payback period method. Cash inflows are expected to be $95 000 in year 1, $150 000 in year 2, $140 000 in year 3, and $190 000 in year 4. The initial investment required is $500 000. Assuming even cash inflows throughout each year, what is the payback period?

a. 3.47 years

b. 3.61 years

c. 3 years

d. 4 years