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: ENT
[{'content': 'Maximum audible tolerance is: \nSelect and explain. \nA. 90 db for 6 hrs, B. 90 db for 8hrs, C. 85 db for 6 hrs, D. 85 db for 8 hrs', 'role': 'user'}, {'content': 'Answer: B \nExplanation: A noise of 90 db, 8hrs a day for 5 days/week is maximum safe limit. No exposure in excess of 115 db is permitted. No impulse noise of intensity > 140 lb is permitted. Persons working in area where noise exceeds 85 db should have pre employment and annual audiograms. Ear plugs offer protection up to 35db and to be used where noise exceeds 85 db.', 'role': 'assistant'}]