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': 'Which of the instrument is used to locate the canal\norifice \nSelect and explain. \nA. Smooth broaches, B. Endodontic explorer, C. Canal opener, D. Gates Glidden drill', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]