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': 'After scaling of a patient, scaler tip is Cleaned by: \nSelect and explain. \nA. Under running H2O for 2 minutes, B. Hot air oven, C. Dipping in phenol disinfectant for 24 hour, D. Chemical vapors', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]