This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Social & Preventive Medicine
[{'content': 'Holding time for Hot air oven with temperature of 1800C \nSelect and explain. \nA. 15 min, B. 30 min, C. 60 min, D. 120 min', 'role': 'user'}, {'content': 'Answer: B \nExplanation: .', 'role': 'assistant'}]