Which of the following is classified as a sexually transmitted disease?

Venereal disease is classified as a sexually transmitted disease (STD) because it encompasses infections that are primarily transmitted through sexual contact. This category includes a variety of infections, such as gonorrhea, syphilis, and chlamydia, which are specifically known to spread through sexual activity. The term itself originates from the Latin "venereus," relating to sexual desire, thereby clearly linking these conditions to sexual transmission.

The other options listed do not fall under the classification of sexually transmitted diseases. Hemorrhoids, for example, are swollen veins in the rectum or anus and are associated with strain or pressure rather than sexual transmission. Cysts, including ovarian cysts, are generally fluid-filled sacs that can occur in various parts of the body and are not connected to sexual activity or transmission. Thus, the only choice that correctly identifies a condition that is spread through sexual interactions is venereal disease.