I would think A
Peer pressure can come from anyone. Not just siblings and people older than you. Peer pressure is usually from a group that one hangs out with.
Vaccines, antibiotics are the major ones. Vaccines inject a dead virus or disease to have your body fight it off and become immune to the disease or virus. Antibiotics like vitamins, are something you take daily to protect the body.
You feel better and look better.
Hope this helps! (: