Cost of the three alternative methods of processing work in an office is stated below:

A-Manual: Total fixed cost PM=3,000

Variable cost per case=48

B-Semi-Automatic:

Total fixed cost PM=9,000

Variable cost per case=28

C-Fully automatic:

Total fixed cost PM=25,000

Variable cost per case=8

Identify the indifference and state your results. For what volume of cases it will be preferred between each of A, B and C?