b$.$ Compare the costs to a level plan that uses inventory to absorb fluctuations. Inventory carrying cost is $$3$ per engine per month. Backlog cost is $$125$ per engine per month. There should not be a backlog in the last month. Set regular production equal to the monthly average of total forecasted demand. Assume that using overtime is not an option. $($Negative amounts should be indicated a minus sign. Leave no cells blank $-$ be certain to enter $"O"$ wherever required. Round average inventory row, Inventory cost row, and Total row values to $1$ decimal.$)$

$\backslash$table$[[$Period$,1,2,3,4,5,6,7,8,$Total$],[$Forecast$,96,135,143,165,125,125,140,143,1,072],[$Output$],[$Regular$],[$Output $-$ Forecast$],[$Inventory$],[$Beginning$],[$Ending$],[$Average$],[$Backlog$],[$Costs$],[$Output$],[$Regular$,p,,,,,,,,],[$Inventory$],[$Backorder$],[$Total$,,,,,,,,,]]$