49- Refer to the Process Flow Diagram for Making a Shirt, with an Additional Worker. Consider only task D, ironing. If an additional ironing worker were hired so that there were three workers working in parallel, what would be the minimum cycle time for the ironing task? Assume that the new worker is identical in capacity to the existing two. a) 2 minutes/unit b) 4 minutes/unit c) 6 minutes/unit d) 12 minutes/unit