FlexSteal,marketed as a Miracle Brush-On Sealant and Baldness Cure,is Manufactured

Multiple Choice

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.
$$\begin{array} { | l | c | c | c | c | c | } \hline & \text { Philadelphia } & \text { Atlanta } & \text { Dallas } & \text { Los Angeles } & \text { Capacity } \\\hline \text { Plant 1 } & 89 & 75 & 93 & 115 & 400 \\\hline \text { Plant 2 } & 120 & 88 & 103 & 93 & 400 \\\hline \text { Plant 3 } & 95 & 82 & 112 & 98 & 400 \\\hline \text { Total Demand } & 350 & 350 & 350 & 350 & \\\hline\end{array}$$ The supply chain manager has explored plant construction costs in two other cities as well as the cost to ship a truckload 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.
$$\begin{array} { | l | c | c | c | c | c | } \hline & \text { Philadelphia } & \text { Atlanta } & \text { Dallas } & \text { Los Angeles } & \text { Cost to Build } \\\hline \text { Plant A } & 94 & 78 & 95 & 95 & \$ 23,500 \\\hline \text { Plant B } & 95 & 88 & 88 & 94 & \$ 26,000 \\\hline\end{array}$$
-How many constraints does the linear programming formulation of a lowest cost solution for the existing set of plants and regional centers contain?

A) 10
B) 7
C) 4
D) 3