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': 'A dental instrument which creates aerosols containing large number of microorganisms is the: \nSelect and explain. \nA. Evacuator, B. Ultrasonic scaler, C. Amalgam condenser, D. Endodontic reamer', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]