Although other birth control options are available, the only one that is 100% reliable is abstinence
the answer for this question is true
The Answer is "true".
This is true. Abstinence is the only guaranteed way to 100% avoid pregnancy and 100% avoid STI's. Birth control methods range between 92% to 99% effective against pregnancy whereas prevention methods for STI's such as condoms are not 100%, in addition some STI's are transmitted through bodily contact with open sores that a condom would not protect you against anyway.
Sexual abstinence is the term used to describe a situation where an individual remains without engaging in any kind of sexual intercourse. As a pregnancy only happens after sex, abstinence is the only method of birth control that has a zero percent failure rate, because abstinence does not have sex. The same goes for STIs.
Dangerous STIs such as Chlamydia ( which is very dangerous to woman) and HIV ( which is very dangerous because it will destroy your immune system) just started to developed in the 1980s