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': 'Aminopeptidase is elevated in obstruction of ? \nSelect and explain. \nA. Ureter, B. Urethra, C. CBD, D. Bladder', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., CBD", 'role': 'assistant'}]