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 following is not used for removing sub gingival calculus \nSelect and explain. \nA. Sickle scalers, B. Hoe, C. Chisel, D. File scaler', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]