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: Radiology
[{'content': 'Which of the following is most radiosensitive tumour? \nSelect and explain. \nA. Astrocytoma, B. Medulloblastoma, C. Craniopharyngioma, D. Teratoma', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. Medulloblastoma', 'role': 'assistant'}]