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
In the perspective of the busy life schedule in the modern society, the accepted minimum period of sexual cohabitation resulting in no offspring for a couple to be declared infertile is: 
Select and explain. 
A. One year, B. One and a half, C. Two years, D. Three years
A: One year
Answer: A: One year 
Explanation: Infertility implies apparent failure of a couple to conceive.
If a couple fails to achieve pregnancy after 1 year of unprotected and regular intercourse,
it is an indication to investigate the couple.