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': 'Stress is defined as: \nSelect and explain. \nA. An applied load or force, B. A deformation resulting from an applied load, C. An external force opposing an applied load, D. An internal force opposing an applied load', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Stress—Force per unit area within a structure subjected to a force or pressure.\nPressure—Force per unit area acting on the surface of a material.\nPhillips dental materials 12th edition page no 48', 'role': 'assistant'}]