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': 'What is the number of Gate Glidden drill used in mid canal region? \nSelect and explain. \nA. 6-May, B. 3, C. 2, D. 1', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]