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': 'Patient with IQ of 60 has - \nSelect and explain. \nA. Mild mental retardation, B. Moderate M..R, C. Severe M.R., D. Profound M.R.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]