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': 'JW 17 according to Grossman’s classification is \nSelect and explain. \nA. Exploring instrument, B. Extirpating instrument, C. Cleaning and shaping instrument, D. Obturating instrument', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]