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': "Rigler's triad consist of all, except: \nSelect and explain. \nA. Intestinal obstruction, B. Cholangitis, C. Gas in bile duct, D. Ectopic gallstone", 'role': 'user'}, {'content': "Answer: B \nExplanation: The triad indicates gallstone ileus. Rigler's triad is: Ectopic gallstone Paial or complete bowel obstruction Gas in the gallbladder or in biliary tree Ref: Sabiston, 18th Edition, Page 1572", 'role': 'assistant'}]