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: Medicine
[{'content': 'The most common hormone other than gastrin, contained in the gastrin-secreting islet cell tumor is - \nSelect and explain. \nA. ACTH, B. Glucagon, C. Melanocyte stimulating hormone, D. Growth hormone releasing factor', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]