You are considering upgrading some manufacturing facilities by purchasing one of three different machines, each with the same production capacity. Machine A costs $33,000, has a life of 40 years, annual maintenance costs of $ 1800, and salvage value of $6500. Machine B costs $22,000, has a life of 20 years, annual maintenance of $2500, and salvage value of $3000. Machine C costs $11,000, has a life of 10 years, annual maintenance of $3500, and no salvage value. Determine the most economical choice, based on minimizing the present value of total costs over a 40-year period. Use an annual discount rate of 8%. Assume that initial machine costs, annual maintenance, and discount rates are constant throughout the analysis period