This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bile duct, Subject name: Surgery
[{'content': 'Most common cause of biliary stricture is:- \nSelect and explain. \nA. CBD stone, B. Trauma, C. Asiatic cholangitis, D. Congenital', 'role': 'user'}, {'content': 'Answer: B \nExplanation: MC cause of benign biliary stricture is laparoscopic cholecystectomy (operative trauma).', 'role': 'assistant'}]