Please answer part D to this question.

A grain cooperative with warehouses in Lincoln, Des Moines and Pierre must meet market demands in Denver, Kansas City, Minneapolis and St. Louis. The following table summarizes data relevant to this week's distribution problem. The number in the first three rows and the + first four columns are the transportation costs/unit from each warehouse to each market. From/to Denver Kansas City Minneapolis St. Louis Supply 6 9 750 Lincoln Des Moines Pierre Demand 6 9 9 4 3 11 700 8 5 6 750 500 14 500 400 400 a. Draw a network diagram representing the problem of minimizing total transportation cost associated with shipping product from the warehouses to meet market demand. b. Formulate an LP model to solve this problem. Please list all the decision variables, objective function and constraints. C. Suppose the cooperative also has a warehouse in Omaha with a supply of 500 units and transportation cost to Denver, Kansas City, Minneapolis and St. Louis of, respectively, 6, 5, 7, and 9. Extend the LP formulation of part (b) to include this option. d. Explain why the cost of meeting the demand in part (C) cannot exceed the cost of meeting demand in part (b). e. Solve the model given in part (b) and (c) using Excel Solver