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': 'Commonest calcifying brain tumor in a child is: \nSelect and explain. \nA. Medulloblastoma, B. Craniopharyngioma, C. Glioma, D. Meningioma', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Craniopharyngeoma', 'role': 'assistant'}]