Which of the following is not a barrier method of birth control?
a. birth control patch
b. condom
c. sponge
d. spermicide

a. birth control patch

Explanation:

The contraceptive patch is simply a sticky material that looks like a shiny adhesive to attach to the skin and is very effective in preventing pregnancy by releasing hormones. For this reason, we can say that this is a hormonal rather than barrier method of birth control.

Estrogen and progesterone hormones are continuously released into the bloodstream through the skin, where they prevent ovaries from releasing eggs and also thicken cervical mucus, making it impossible for sperm to reach the egg. The patch is not transparent, so this contraceptive method may be visible depending on where it is placed and the type of clothing.

that is so

obviously, the latter.