Her operations manager is considering a new$$ plan, which begins in January with units of inventory on hand. Stockout cost of lost sales is $$$ per unit. Inventory holding cost is $$$ per unit per month. Ignore any$$ idle$-$time costs. The plan is called plan A$.$

Plan$$ A: Vary the workforce level to execute a strategy that produces the quantity demanded in the prior month. The December demand and rate of production are both units per month. The cost of hiring additional workers is $$$ per unit. The cost of laying off workers is $$$ per unit. Evaluate this plan. $($Enter all responses as whole numbers$.)$

$$Note: Both hiring and layoff costs are incurred in the month of the change. For$$ example, going from in January to in February incurs a cost of layoff for units in February.

Part $2$