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': "In gallbladder mucocoele where is the stone usually impacted \nSelect and explain. \nA. Hartmann's pouch, B. Calot's triangle, C. CBD, D. Duodenum", 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]