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': 'Ultimate tensile strength refers to: \nSelect and explain. \nA. Stress before rupture, B. Stress after rupture, C. Longitudinal compressive strength, D. Horizontal compressive strength', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Tensile strength (ultimate tensile strength)—Tensile stress at the instant of fracture.\nThe ultimate tensile strength is defined as the tensile stress within a structure at the point of rupture.\nPhillips dental materials 12th edition page no 49,57', 'role': 'assistant'}]