The key difference between transportation and transshipment models is that 1) Transportation model minimizes cost and transshipment model maximizes profit 2) Transportation model involves indirect shipments and transshipment model involves direct shipments 3) Transportation model has no intermediate nodes, but the transshipment model has intermediate nodes 4) They are the same and no differences exist Question 9 (10 points) In the supply chain network design model, how many additional variables will be needed to have the option of selecting suppliers if fixed costs are given? 1) 2 2) 1 3) 3 4) 5