The president of Hill Enterprises, Terri Hill, projects the firm's aggregate demand requirements over the next $8$ months as follows:

$\backslash$table$[[$January$,1,500,$May,$2,200],[$February$,1,600,$June,$2,300],[$March$,1,600,$July,$1,700],[$April$,1,900,$August,$1,300]]$

$$20$ per unit per month. Ignore any idle$-$time costs. The plan is called plan B$.$ capacity is limited to $1,000$ units per month. Evaluate this plan by computing the costs for January through August.

$\backslash$table$[[$Period$,$Month,Demand,Production,$\backslash$table$[[$Ending$],[$Inventory$]],\backslash$table$[[$Subcontract$],[$Units$]]],[0,$December,,,$200,],[1,$January,$1,500,1,300,200,],[2,$February,$1,600,1,300,300,],[3,$March,$1,600,1,300,300,],[4,$April,$1,900,1,300,600,],[5,$May,$2,200,1,300,900,],[6,$June,$2,300,1,300,1000,],[7,$July,$1,700,1,300,400,],[8,$August,$1,300,1,300,0,]]$