This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
To remove non working side interference, reduce: 
Select and explain. 
A. Maxillary supporting cusps., B. Mandibular supporting cusps., C. Supporting cusps of both the arches., D. Either of the arch's supporting cusps should be reduced.
D: Either of the arch's supporting cusps should be reduced.
Answer: D: Either of the arch's supporting cusps should be reduced. 
Explanation: None