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': 'Why is it called Cu T 200 \nSelect and explain. \nA. 200 sqmm of Cu over loop, B. 200 mm of Cu over loop, C. For 200 days, Cu concentration does not changes, D. 200 sqcm of Cu over loop', 'role': 'user'}, {'content': 'Answer: A \nExplanation: In Cu T 200, the number included in the name of the device refer to the surface area in sq.mm of the copper on the device Reference : Park&;s textbook of preventive and social medicine,23rd edition, Page no: 496', 'role': 'assistant'}]