FlexSteal, marketed as a miracle brush-on sealant and baldness cure, is manufactured at three plants that are struggling to keep up with the demand at the four regional centers. The cost to ship a truckload from each of the existing plants to the regional centers is shown in the table. Note that the capacity and the total demand are both measured in truckloads. The supply chain manager has explored plant construction costs in two other cities as well as the cost to ship a truckioad from each of the plants to the regional centers. The current plan is to build another plant with a capacity of 400 to allow room for sales growth. The construction cost for the new plants and cost to ship to each of the regional centers is shown here. How many constraints does the linear programming formulation of a lowest cost solution for the existing set of plants and regional centers contain? 7 4 10