A company is considering the purchase of an asset which costs $56,000 and has an estimated scrap value of $9,000 after 4 years. The asset is expected to increase revenue by $20,000 a year before maintenance costs of $3,500 a year. Assuming a tax rate 42%, compute the net present value of the investment using a 6% interest rate and depreciation charges obtained from: A: the straight-line method of depreciation ($1390.20) B: the sum of years digits method of depreciation ($1887.93) C: the double declining balance method for two years followed by the straight-line method ($2330.72) Cannot use Excel.