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': 'Tip diameter of a no. 245 bur is ______mm \nSelect and explain. \nA. 0.8, B. 1.2, C. 1, D. 1.5', 'role': 'user'}, {'content': 'Answer: A \nExplanation: It is inverted cone shape with diameter .8mm and length 3mm.', 'role': 'assistant'}]