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
[{'content': 'Following movement of tip is seen in Giromatic hand piece: \nSelect and explain. \nA. Reciprocating 90° arc, B. 180° arc, C. Oscillating to and fro moments, D. Vertical displacement of tip', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]