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: Surgery
[{'content': 'All are true foe annular pancreas except \nSelect and explain. \nA. Upper GI series is IOC, B. Duodenal obstruction present, C. ERCP is done, D. Non - rotation of gut', 'role': 'user'}, {'content': 'Answer: A \nExplanation: upper GI series is not the investigation of choice.They are plain X-ray abdomen,ERCP and Radioscopic study , Barium meal. SRB,5th,712', 'role': 'assistant'}]