This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T., Subject name: Medicine
[{'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: Ans. is 'b' Sclerosing cholangitis (Ref. Sutton Radiology, 6/e, p. 957).First go through the causes of air in billary tract:Following surgery or endoscopic intervention on biliary tract.Gall stone fistulaMalignant fistulaPhysiological lax sphincterPerforation of peptic ulcer in biliary tract.Now let's see why option (b) is to be preferred.Option (a)Gall stone ileus is obvious to everyone.Option (c)Carcinoma gall bladder can cause air in biliary tract by forming malignant fistulae.Option (d)Endoscopic papillotomy- Any operation on biliary tract can cause air in biliary tract, moreover endoscopic papillotomy can lead to lax sphincter.", 'role': 'assistant'}]