Scenario 8 The Labor Contract at the Plant Prohibits Both Overtime and Problem

Scenario 8.2 - Willow
A company faces the aggregate planning problem shown in the table below.Cost of regular production is $8 per unit,the cost of producing the same unit on overtime is $15,the cost of subcontracting is $12 per unit,and the cost of carrying a unit in inventory from one month to the next is $6.
$$\begin{array} { | l | c | c | c | c | c | } \hline & \text { January } & \text { February } & \text { March } & \text { April } & \text { May } \\\hline \text { Forecast } & 400 & 800 & 1200 & 700 & 300 \\\hline \text { Beginning Inventory } & 100 & & & & \\\hline \text { Regular Time } & & & & & \\\hline \text { Overtime } & & & & & \\\hline \text { Subcontracting } & & & & & \\\hline \text { Ending Inventory } & & & & & \\\hline\end{array}$$ The labor contract at the plant prohibits both overtime and subcontracting output to exceed 400 units in any five-month window.The plant capacity is 20 units per day produced using two shifts and the plant runs seven days a week.By policy,management wants to avoid stockouts.
-How many units are produced using overtime in the optimal aggregate plan developed to address Scenario 8.2?

A) 360
B) 200
C) 400
D) 280