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': 'Commonest site of extramedullary relapse of \nSelect and explain. \nA. CNS, B. Lung, C. Liver, D. Testis', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., CNS", 'role': 'assistant'}]