One worker is assigned to each stage. The activity time (in [minute/unit]) for each stage is: A B C D Activity time per unit (min) 0.1 0.2 0.3 0.4 (a) Which stage is the bottleneck? What is the process capacity in [units/hr]? (b) Suppose the steps in activity D are made easier, so the activity time per unit in step D is reduced by 50% (to 0.2 [min/unit]). By how much does the capacity of the entire process increase in [units/hr]