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': 'Most important prognostic indicator for wilms tumor \nSelect and explain. \nA. Nuclear grade, B. Histological type, C. Size, D. Pathological staging', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Histology is Most important prognostic indicator for wilms tumor\nStage of tumor is Most important prognostic indicator for RCC.', 'role': 'assistant'}]