A service process is described by the above flowchart. After going through workstation A, an order needs to be processed by one of the three lines, B1-C1D1, B2-C2-D2, or B3-C3-D3 (in other words, they are substitutable). Finally, all orders need to go through workstation E. The capacities of the individual workstations are given as follows: - Workstation A has a capacity of 4 orders/hour - Workstation B1, B2, and B3 have the same capacity of 5 orders/hour - Workstation C1, C2, and C3 have the same capacity of 2 orders/hour - Workstation D1, D2, and D3 have the same capacity of 3 orders/hour - Workstation E has a capacity of 5 orders/hour Which workstation is the bottleneck? Workstation A Workstations B1, B2, and B3 Workstations C1, C2, and C3 Workstations D1, D2, and D3 Workstation E