The president of Hill Enterprises, Terri Hill, projects the firm's aggregate demand requirements over the next 8 months as follows: January 1,500 May 2,300 February 1,600 June 2,100 March April 1,700 1,700 July August 1,800 1,400 Her operations manager is considering a new plan, which begins in January with 200 units of inventory on hand. Stockout cost of lost sales is $60 per unit. Inventory holding cost is $20 per unit per month. Ignore any idle-time costs. Evaluate the following plans D and E. Plan D: Keep the current workforce stable at producing 1,600 units per month. In addition to the regular production, another 20% of the normal production units can be produced in overtime at an additional cost of $50 per unit. A warehouse now constrains the maximum allowable inventory on hand to 600 units or less. Note: Do not produce in overtime if production or inventory are adequate to cover demand. Plan D Month Demand Production (Units) O.T. Production (Units) Ending Inventory Stockouts (Units) 0 December 200 1 January 1,500 1,600 2 February 1,600 1,600 3 March 1,700 1,600 4 April 1,700 1,600 5 May 2,300 1,600 6 June 2,100 1,600 7 July 1,800 1,600 8 August 1,400 1,600