Burn Incorporated purchased a $670,000 machine to manufacture a specialty tap for electrical equipment. The tap is in high demand and Burn can sell all that it could manufacture for the next 10 years. To encourage capital Investments, the government exempts taxes on profits from new Investments In this type of machinery. This legislation most likely will remain in effect in the foreseeable future. The equipment is expected to have 10 years of useful life and no salvage value at the end of this 10-year period. The firm uses straight-line depreciation. The net cash Inflow is expected to be $144,000 each year. Burn uses a discount rate of 10% In evaluating its capital Investments. Assume that after-tax cash Inflows occur evenly throughout the year. The estimated payback period for this proposed Investment, In years, Is (rounded to two decimal places):

a) 4.65

b) 7.62

c) 5.91

d) 5.53

e) 6.15