XYZ is a manufacturer in need of an aggregate plan for July through December. The company has gathered the following data. Compare the cost of two different strategies and choose the most cost effective strategy among them. Demand Costs Other data July 400 Holding cost $5/DVD/month Current work force 6 people (june) Aug. 500 Subcontracting $40/DVD 2 hours Labour hours/product $10/hour Workdays/month 20days Sep. 550 Regular time labour Oct. 700 Over time Labour $15(above 8 hours) Nov. 800 Hiring costs $30/worker Dec. 700 Layoff cost $50/worker