This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Child psychiatry, Subject name: Psychiatry
[{'content': 'Severe mental retardation is \nSelect and explain. \nA. 50 - 69, B. 35 - 49, C. 20 - 34, D. Less than 20', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Mental retardation level IQ range Mild 50-69 Moderate 35-49 Severe 20-34 Profound < 20 (Ref: A sho textbook of psychiatry, Niraj Ahuja,7th edition, pg no 156)', 'role': 'assistant'}]