Southeast Soda Pop, Inc., has a new fruit drink for which it has high hopes. John Mittenthal, the production planner, has assembled the following cost data and demand forecast:

$\backslash$table$[[$Quarter$,$Forecast$],[1,1,600],[2,1,100],[3,1,600],[4,900]]$

$\backslash$table$[[$COSTS$/$OTHER DATA$],[$Previous quarter's output $=1,500$ cases$],[$Beginning inventory $=0$ cases$],[$Stockout cost $=$$$140$ per case$],[$Inventory holding cost $=$$$30$ per case at end of quarter$],[$Hiring employees $=$$$30$ per case$],[$Terminating employees $=$$$60$ per case$],[$Subcontracting cost $=$$$50$ per case$],[$Unit cost on regular time $=$$$40$ per case$],[$Overtime cost $=$$$20$ extra per case$],[$Capacity on regular time $=1,800$ cases per quarter$]]$

John's job is to develop an aggregate plan. The three initial options he wants to evaluate are:

$$ Plan A: a strategy that hires and fires personnel as necessary to meet the forecast.

Plan B: a level strategy that produces $1,200$ cases per quarter and meets the forecast demand with inventory and subcontracting.

Plan C: Keep a stable workforce by maintaining a constant production rate equal to the average requirements and allow varying inventory levels.

Which strategy is the lowest$-$cost plan?