A plant manufactures two different products: P and Q. Selling prices and weekly market demands are shown in the following table. Each product uses raw materials with costs as shown in the table. The plant has two different machines, A and B, each available for 2,400 minutes per week. There is a single unit of each machine, and each can process both products, but can work on only one unit of material at a time. Moreover, the plant has a fixed operating cost of $12,000/week. Product Unit Selling Price Unit Raw Material Cost Unit Revenue Margin Weekly Demand P $190 $100 100 units Q $200 $80 50 units Considering that each machine is available for 2,400 minutes per week, which of the following is the constraint? Machine A Machine B Product P Product Q Market demand