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: Pathology
Grading of cancer based on ? 
Select and explain. 
A. Differentiation, B. Tumor necrosis, C. Tumor size, D. Lymph node status
A: Differentiation
Answer: A: Differentiation 
Explanation: Ans. is 'a' i.e. Differentiation