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': 'What does the point X represents in the following diagram? \nSelect and explain. \nA. Fracture, B. Yield point, C. Yield strength, D. Ultimate strength', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]