This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Intellectual disability, communication, autism, and ADHD, Subject name: Psychiatry
[{'content': 'Severe mental retardation is - \nSelect and explain. \nA. 50-70, B. 35-50, C. 20-35, D. <20', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans is 'c' i.e. 20 - 35 o Normal IQ - 90-109;o Borderline IQ - 70-89;o Mild mental retardation IQ - 50-69;o Moderate mental retardation IQ -35-49;o Severe MR IQ - 20-34;o Profound MR IQ - 0-19.", 'role': 'assistant'}]