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
Gleason's staging is done in - 
Select and explain. 
A. Ca prostate, B. Ca Pancreas, C. Ca kidney, D. Ca Cx
A: Ca prostate
Answer: A: Ca prostate 
Explanation: Answer is 'a' i.e. Ca. prostate