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 elastic or plastic deformation to fracture a material is its: \nSelect and explain. \nA. Toughness, B. Brittleness, C. Young's Modulus, D. Proportional limit", 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]