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': 'BMI to classify obesity should be ? \nSelect and explain. \nA. ≥20, B. ≥30, C. ≥40, D. ≥50', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]