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': 'Which of the following organs is the most common site of origin of the tumour associated with the Zollinger-Ellison syndrome - \nSelect and explain. \nA. Duodenum, B. Lymph nodes, C. Spleen, D. Pancreas', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Duodenum", 'role': 'assistant'}]