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: Dental
[{'content': 'The strain that occurs when a material is stressed to its proportional limit is: \nSelect and explain. \nA. Resilience, B. Maximum flexibility, C. Toughness, D. Elastic limit', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]