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 is the value of poisons ratio for ideal isotropic material: \nSelect and explain. \nA. 0.3, B. 0.4, C. 0.5, D. 0.6', 'role': 'user'}, {'content': 'Answer: C \nExplanation: For most engineering materials poisons ratio is 0.3', 'role': 'assistant'}]