This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Definitions & Concepts, Subject name: Social & Preventive Medicine
[{'content': 'Contraceptive Efficacy is measured by:- \nSelect and explain. \nA. Pearl index only, B. Pearl index and Life table analysis, C. Life table analysis and Couple protection rate, D. Pearl index and Couple protection rate', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Contraceptive efficacy: Is assessed by measuring the number of unplanned pregnancies that occur during a specified period of exposure and use of a contraceptive method. Two methods used are: - Pearl index - Life table analysis Life table analysis as measure of contraceptive efficacy is a better measure than Pearl Index', 'role': 'assistant'}]