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
Which of the following means of contraception is the best method to achieve Net Reproductive Rate (NRR)=1? 
Select and explain. 
A. IUCD, B. Condoms, C. Vasectomy, D. Oral pills
C: Vasectomy
Answer: C: Vasectomy 
Explanation: NRR is the most significant indicator of feility. Sterilization accounts for 80% of effective couple protection and hence is the best method among the above choices.