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': 'Peaso reamer is \nSelect and explain. \nA. No. 4= 1.3 mm in size, B. Used for lingual shoulder removal, C. Flame shaped, D. high speed engine driven', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]