An appliance company operates $3$ production plants in the United States. After production, they ship the appliances to $4$ regions of the country $($North$,$ South, East and West$).$ The file below with the model summarizes shipping costs per unit between all plants and regions, as well as plant capacities and estimated demands for each region. The appliance company wants to minimize shipping costs while meeting demand and without exceeding the plants' capacities. The second attachment below contains the sensitivity report of the solved model.

Final$\_$Shipping$\_$Model.pdf

Final$\_$Shipping$\_$Sensitivity.pdf

Which of the constraints are binding?

Note: This is a multiple answer question. This means one or more of the choices may be correct. You will receive partial credit for each correct answer. You will lose partial credit for each incorrectly selected answer $($this is merely to rule out selecting all answers as an optimal strategy$),$ so if you are not sure, it is better to leave the answer unchecked. For example, if there are two correct answers to a question and you only select one of them, you'll receive $50\%$ of the credit. If you select one correct and one incorrect option, you will receive no credit as the positive and negative partial credit cancel each other out. You overall score on the question however cannot be negative.

a$.$

Plant $1\text{'}$s capacity constraint

b$.$

Plant $2\text{'}$s capacity constraint

c$.$

Plant $3\text{'}$s capacity constraint

d$.$

Demand in the North region

e$.$

Demand in the South region

f$.$

Demand in the East region

g$.$

Demand in the West region