This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Misc., Subject name: Medicine
[{'content': 'Hyperglycemia occurs after what % of beta cell mass is destroyed: \nSelect and explain. \nA. 20%, B. 40%, C. 60%, D. 80%', 'role': 'user'}, {'content': 'Answer: D \nExplanation: * Type 1 diabetes mellitus is characterized by an inability to produce insulin endogenously. * Based on a series of histopathology studies, it is commonly stated that the onset of clinical symptoms corresponds to an 80-95% reduction in beta cell mass', 'role': 'assistant'}]