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
[{'content': 'Grading of cancer based on ? \nSelect and explain. \nA. Differentiation, B. Tumor necrosis, C. Tumor size, D. Lymph node status', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e. Differentiation", 'role': 'assistant'}]