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: Social & Preventive Medicine
[{'content': 'Nova T has \nSelect and explain. \nA. Silver core, B. Platinum core, C. Copper core, D. Iron core', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]