Consider the following steps in production, planning and control:
1. Capacity planning
2. Material requirement planning
3. Purchasing
4. Design decisions
Which one of the following is the correct sequence of the above steps in operations management?
(a) 2-3-4-1 (b) 2-4-3-1
(c) 4-1-2-3 (d) 1-2-4-3