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': 'Severe wasting is – \nSelect and explain. \nA. < 60%, B. < 70%, C. < 80%, D. < 90%', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]