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': 'Net reproductive rate of 1 can be achieved if Couple production rate is more than: \nSelect and explain. \nA. > 30%, B. >40%, C. >50%, D. >60%', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Demographers are of the view that a net reproductive rate of 1 can be achieved if couple protection rate (CPR) is > 60%. CPR is based on observation that 50-60% of bihs in a year are of bih order 3 or more. Thus attaining a CPR of 60% or more will be equivalent to cutting off almost all third or higher order bihs leaving 2 or less children per couple or net reproductive rate around 1. Ref: Park 21st edition, page 456. Chapter: Demography and family planning.', 'role': 'assistant'}]