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: Pediatrics
[{'content': 'Condition a/w MR - \nSelect and explain. \nA. Trisomy 21, B. Fragile - X, C. Homocystinemia, D. All', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. is All', 'role': 'assistant'}]