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': 'The root canal instrument most likely to break during use is a \nSelect and explain. \nA. File, B. Broach, C. Reamers, D. Spreaders', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]