Question 4) (25 points) Consider a transportation problem. There are a set of suppliers and a set of customers in a region. The customers have their known demand of a specific product. Suppliers have supply capacities for the product. An operations manager wants to make shipment decisions, i.e., how many items to ship from each supplier to each customer, subject to the demand requirements and supply capacities. The demand and supply information are presented below. A shipping cost is charged for shipping each unit of item from a supplier to a customer. The cost information is summarized below. According to this cost matrix, for example to ship 100 units of the item from supplier 2 to customer B, a shipping cost of 4100=400 is charged. The goal is to minimize the total transportation costs. (Submit your Excel file)