what is the needed information?!

Q1) Evaluate each plan and find out which one is better in terms of total costs. - Plan 1: for the manufacturer is to maintain a constant workforce throughout the 6-month period. we assume that the production per day is average requirements ( average production per day) and that we have a constant workforce, no overtime or idle time, no safety stock, and no subcontractors. The firm accumulates inventory during the slack period of demand, January through March, and depletes it during the higher-demand warm season, April through June. We assume beginning inventory = 0 and planned ending inventory = 0. - Plan 2: is to maintain a constant workforce at a level necessary to meet the lowest demand month and to meet all demand above this level by subcontracting. Please use the following information : Costs table: Inventory carrying cost SR 3 per unit per month Subcontracting cost per unit SR 17 per unit Average pay rate SR 10 per hour (S80 per day for 8 hours working per day) Labor-hours to produce a unit 4 hours per unit Monthly forecasts: Month Jan Feb Mar Apr May Jun Expected Demand 800 500 600 1,050 1,150 1,100 Production Days 21 18 18 22 19 20