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: Psychiatry
[{'content': 'A person is said to be mentally retarded when IQ is \nSelect and explain. \nA. < 100, B. <90, C. <80, D. <70', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Normal IQ → 90-109;\nBorderline IQ → 70-89;\nMild mental retardation IQ → 50-69;\nModerate mental retardation IQ → 35-49;\nSevere MR IQ → 20-34;\nProfound MR IQ → 0-19.', 'role': 'assistant'}]