This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gall Bladder & Bile Ducts, Subject name: Surgery
[{'content': "Rigler's triad is a feature of \nSelect and explain. \nA. Post laparotomy obstruction, B. Gall stone Ileus, C. Carcinoma Head of Pancreas, D. Barotrauma", 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. (b) Gall stone IleusRef: Sabiston 20th edition page 1506Rigler's Triad is seen in gall stone ileus:* Tumbling obstruction of small intestine* Pneumobilia* Cholecysto Enteric fistulaMost common in old ageObstruction most common in terminal ileum", 'role': 'assistant'}]