Consider the three step process below

[A -> B -> C]

Setup time (minutes) 30 40 60

Processing time (min/unit) 5 2 1

This process requires a setup in each step before each batch and maintains a strict batch flow discipline (i.e., batches are never split). If the batch size varies between 1 and 20 units, which of the following statements is always true?

a.Step B is the bottleneck of this process

b.Step A is the bottleneck of this process

c.Step C is the bottleneck of this process

d.Step A or Step B is the bottleneck of this process

e.Any of the steps (i.e., Step A, Step B or Step C) can be the bottleneck of this process

f.Step A or Step C is the bottleneck of this process

g.Step B or Step C is the bottleneck of this process