This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Demography and family planning, Subject name: Social & Preventive Medicine
[{'content': 'In Cu 380A, 380 represents \nSelect and explain. \nA. Number of turns of copper wire, B. Surface area of CuT in sq.mm, C. Surface area of Cu in sq.mm, D. Effective life of CuT in quaers', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The numbers included in the names of the devices refer to the surface area (in sq.mm) of the copper on the device. Metallic copper has a strong anti-feility effect.Park 23e pg: 496', 'role': 'assistant'}]