Diaphragms, cervical caps and vaults prevent conception by :

Blocking the entry of sperms through the cervix.

The correct answer is Option (3) – Blocking the entry of sperms through the cervix.

Diaphragms, cervical caps and vaults are also barriers made of rubber that are inserted into the female reproductive tract to cover the cervix during coitus. They prevent conception by blocking the entry of sperms through the cervix. They are reusable. Spermicidal creams, jellies and foams are usually used alongwith these barriers to increase their contraceptive efficiency.