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: Surgery
[{'content': 'Which of the following is the most common astrocytoma in children? \nSelect and explain. \nA. Grade 1 astrocytoma, B. Grade 2 astrocytoma, C. Grade 3 astrocytoma, D. Grade 4 astrocytoma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Pilocytic astrocytoma (Grade 1) is the most common astrocytoma in children.', 'role': 'assistant'}]