A flu vaccine producer needs to figure out the cheapest way to distribute pre-filled syringes from their plants in Pittsburgh, PA and Staunton, VA to pharmacy distribution centers in the area. Use the network flow model illustrated below to see the supply, demand, and unit shipping cost for the flu shots. a. Set up the problem in Excel and solve for the optimal solution that minimizes shipping costs while fulfilling orders for the producer. b. Suppose that because of the truck driving shortage, only 1,000 prefilled syringes can be shipped over any one are of the model. Would this change your optimal solution? Why or why not