This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Non communicable diseases, Subject name: Social & Preventive Medicine
[{'content': 'A person is obese if he has weight for height - \nSelect and explain. \nA. 1 SD from median weight for height, B. 2 SD from median weight for height, C. 3 SD from median weight for height, D. None', 'role': 'user'}, {'content': "Answer: B \nExplanation: Park's textbook of preventive and social medicine 23rd edition In epidemiological studies it is conventional to accept +2SD from the median weight for height as a cutoff point for obesity.", 'role': 'assistant'}]