Assertion: Periodic abstinence is a method in which couples avoid from coitus from day 17 to 27 of menstrual cycle.
Reason: Periodic abstinence is a very effective method and 100% sure of birth control.

Both Assertion (A) and Reason are false (F )

The correct answer is Option (4)- Both Assertion (A) and Reason are false (F).

Periodic abstinence is a natural method in which the couples avoid or abstain from coitus from day 10 to 17 of the menstrual cycle when ovulation could be expected. Periodic abstinence is a method in which couples avoid coitus during the fertile period of the woman's menstrual cycle to prevent pregnancy. However, it is not considered 100% effective, as there is still a risk of unintended pregnancy. The effectiveness of periodic abstinence depends on various factors, including the regularity of the menstrual cycle and the accuracy of identifying the fertile period. It is not considered a foolproof method of birth control.

This method may reduce the chances of pregnancy by about 80 % . However , a great care is needed in its use. Ovum remains alive for above 1−2 days and sperm survives for about 3 days.