A. 1; the common cold can be transmitted through contact with infected individuals, or even surfaces they have touched, so frequent hand-washing can help to combat its spread.
B. 3; gonorrhea is a sexually-transmitted disease, so not engaging in any form of sexual activity is the only way to ensure that one will not contract it.
C. 2; chicken pox, among many other diseases, can be combated by a vaccine, in which a patient is given a small dose of the disease in dormant form to familiarize their immune system with it, before the person comes into contact with the live strain.
