This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Physiology
[{'content': 'Amylin is secreted by which of the following cells of Islets of Langerhans? \nSelect and explain. \nA. a cells, B. b cells, C. d cells, D. F cells', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The beta cells, constituting about 60 percent of all the cells of the islets, lie mainly in the middle of each islet and secrete insulin and amylin, a hormone that is often secreted in parallel with insulin, although its function is not well understood.', 'role': 'assistant'}]