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
Working side contact means: 
Select and explain. 
A. Contact on lateral movement., B. Contact on medial movement., C. No contact on lateral movement., D. None of the above.
A: Contact on lateral movement.
Answer: A: Contact on lateral movement. 
Explanation: None