$4.($Chapter $10)$ 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 values $($Salvage values are provided in the table$).$ If the town's MARR is $15\%$ per year use the Incremental Benefit Cost ratio method to determine which system is the best. Draw cash flow diagrams for each alternative as well as incremental scenarios before calculating Incremental Benefit Cost ratio. $(20$ Points$)$