Which of the following is an unreliable form of birth control? 

A)  spermicide 
B)  a douche 
C)  a condom 
D)  a cervical cap

Cervical Cap

A small, cup-shaped contraceptive device made of silicone or latex that fits over the cervix to prevent pregnancy by blocking sperm from entering the uterus.

Douche

A method of washing or cleaning out a body cavity, vaginal canal, or another bodily part with a stream of fluid.

Spermicide

A contraceptive substance that destroys sperm, inserted vaginally prior to intercourse to prevent pregnancy.