answer is C. please do step by step and do not use DN!

A town in northern Colorado is planning on investing in a water purification system. Three mutually exclusive systems have been proposed, and their capital investment costs and net annual benefits are the following (salvage values are negligible). System EOY B answer: C 0 -S160,000-$245,000-$200,000 1 80,000 120,000 80,000 2 70,000 100,000 80,000 3 60,000 80,000 80,000 4 50,000 60,000 80,000 If the town's MARR is 10% per year, use the B-C ratio method to determine which system is best