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
The main action of the reciprocating arm is 
Select and explain. 
A. Reciprocates the action of the retentive arm, B. Reciprocation of vertical displacement, C. To provide stability to the denture, D. None of the above
A: Reciprocates the action of the retentive arm
Answer: A: Reciprocates the action of the retentive arm 
Explanation: None