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
For NRR to be 1, couple protection rate should be? 
Select and explain. 
A. 20%, B. 40%, C. 60%, D. 80%
C: 60%
Answer: C: 60% 
Explanation: To achieve the demographic goal of NRR 1 the couple protection rate (CPR) should have to be achieved by 60% far beyond the present level. The objective was to assess the contraceptive prevalence rate by different methods and to find out the correlation of different biosocial factors with the use of contraception.