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
Most important prognostic indicator for wilms tumor 
Select and explain. 
A. Nuclear grade, B. Histological type, C. Size, D. Pathological staging
B: Histological type
Answer: B: Histological type 
Explanation: Histology is Most important prognostic indicator for wilms tumor
Stage of tumor is Most important prognostic indicator for RCC.