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': 'Piezoelectric handpiece \nSelect and explain. \nA. Is ultrasonic instrument, B. Linear motion, C. More efficient than magnetostrictive handpiece, D. v All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]