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': 'Double-bubble sign in X-ray is seen in \nSelect and explain. \nA. Colon carcinoma, B. Duodenal atresia, C. Acute pancreatitis, D. Perforation', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Duodenal atresia', 'role': 'assistant'}]