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': "Gleason's staging is done in - \nSelect and explain. \nA. Ca prostate, B. Ca Pancreas, C. Ca kidney, D. Ca Cx", 'role': 'user'}, {'content': "Answer: A \nExplanation: Answer is 'a' i.e. Ca. prostate", 'role': 'assistant'}]