A national catalos and intemet retaller has three warehouses and three major distribution centers located around the country Normally, hems are shipped directly from the warehouses to the distribution centers; howevet, each of the distribution centers can also be used as an intermediate transhhipment. point. The transportation costs (S/unit) between warehoures and distribution centers, the supply at the warehouses (100 units), and the demand at the distribution centers (100 units) for a specific week are shown in the following table: The transportation costs ( $/ unit) between the distribution centers are Determine the optimal shipments between warehouses and distribution centers to minimize total transportation costs