This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Demography and family planning, Subject name: Social & Preventive Medicine
Which of the following is impoant in calculation of pearl index 
Select and explain. 
A. Number of aboions, B. Total accidental pregnancies, C. Socioeconomic status, D. Total gestational period
B: Total accidental pregnancies
Answer: B: Total accidental pregnancies 
Explanation: Pearl index is defined as the number of failures per 100 woman years of exposure (HWY) Failure rate per Hundred Women Years = Total accidental pregnancies X 1200/ Total months of exposure Reference : Park&;s textbook of preventive and social medicine, 23rd edition, Page no: 510