Use Excel's Solver to find the minimum cost solution for the transportation problem described below. Attach all Excel printouts (e.g., screenshots) as Exhibits. There are three sources with capacities 20, 30, and 75 units of a product, respectively. There are also three destinations with demands 40, 60, and 55 units of the same product, respectively. The unit transportation costs from the three sources to the three destinations are given in the following table: Destination 1 Destination 2 Destination 3 Source 1 30 12 5 Source 2 10 14 12 Source 3 20 11 25 b) The optimal solution is: The minimum transportation cost is: c) (Do alternative optimal solutions exist? Fully explain your answer.