I need a solution of this question quickly please

find an optimization model

By the end of Feb, the company has 100 units in stock, By the end of Feb, the company has 12 workers, each worker can produce 15 unit/month -hiring cost = $200/person -Firing cost =$400/person -holding cost =$50/unit-month Production set up cost is $500/set up company would like to have 200 units in stock by the end of planning horizon Month Period Demand March April June July 1 2 3 4 520 720 520 620 -Sub contracting cost is $13 - Production cost is $6 Find an optimization model