11 Alternative X has a first cost of $20,000, an operating cost of $9,000 per year, and a $5,000 salvage value after 2 years. Alternative Y will cost $35,000 with an operating cost of $4,000 per year and a salvage value of $7,000 after 4 years. At a MARR of 12% per year, when comparing the alternatives, the equation of PWx is written as: out of beston O a. PWX = -20,000 -9000(P/A,12%,4) + 5000(P/F, 12%,4)-15000(P/F.12%.4) O b. PWX - -20,000 - 9000(P/A, 12%:4) + 5000(P/F.12%,2)-15000(P/F.12%,2) c None of these answers O d. PWX = -20,000 + 9000(P/A.12%,4) + 5000(P/F.12%,4)-15000(P/F, 12%,2)