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': 'Chronological age 10 years, mental age 4 years. What that person called as? \nSelect and explain. \nA. Idiot, B. Imbecile, C. Normal, D. Genius', 'role': 'user'}, {'content': 'Answer: B \nExplanation: IQ of this child = 4/10\xa0x 100 = 40\nImbecile child has IQ between 25-49.', 'role': 'assistant'}]