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: Social & Preventive Medicine
[{'content': 'Nodal centre in case of disaster management \nSelect and explain. \nA. PHC, B. District, C. Sub centre, D. CHC', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]