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': 'USG - KUB in evaluation of carcinoma prostate is not useful for \nSelect and explain. \nA. LN involvement, B. Residual volume, C. Biopsy, D. Hydronephrosis', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Biopsy is taken from transrectal ultrasound (TRUS).', 'role': 'assistant'}]