Ahmad is an electrical engineer and he want to invest in one of the following three choices. Project A has an initial cost of $50000, and the annual operating cost is $10000, where the service life is 2 years. Project B has an initial cost of $90000 and the annual operating cost is $7000, service life is 4 years. Project C will cost $140000 initially and the annual operating cost of $5000, service life is 8 years, the salvage value of the project C equipment is estimated to be $15000. While Project A and B have no salvage value. Which Project should be selected by Ahmad? Use present worth analysis at an interest rate of 10% per year.