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
Best index for measuring efficacy of contraception is, 
Select and explain. 
A. Pearl Index, B. Life Table Analysis, C. Couple protection rate, D. None of the above
B: Life Table Analysis
Answer: B: Life Table Analysis 
Explanation: None