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: Radiology
[{'content': 'Air in biliary tract is seen in all except: \nSelect and explain. \nA. Gall stone ileus, B. Sclerosing cholangitis, C. Carcinoma gall bladder, D. Endoscopic papillotomy', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Sclerosing Cholangitis', 'role': 'assistant'}]