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': 'Commonest type of cancer of the renal pelvis and upper ureter is - \nSelect and explain. \nA. Transitional cell carcinoma, B. Adenocarcinoma, C. Squamous cell carcinoma, D. Nephroblastoma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]