Answer:
Differential cost of producing Product C = $0
Step-by-step explanation:
A company should process further a product if the additional revenue from the split-off point is greater than than the further processing cost.
Also note that all cost incurred up to the split-off point (the cost of crushing) are irrelevant to the decision to process further .
$
Sales revenue after the split off point (Product C) 58
Sales revenue at the split-off point (Product B 33
Additional sales revenue per unit 25
Further processing cost (25)
Differential cost of Product C 0
Differential cost of producing Product C = $0
Note that the cost incurred up until the split off point was not included because it is Irrelevant to the decision to process further. It has already been incurred , hence it is a sunk cost