Which of the following is a common sexually transmitted infection (STI)?

Chlamydia is a common sexually transmitted infection (STI) caused by the bacterium Chlamydia trachomatis. It is primarily transmitted through sexual contact, including vaginal, anal, and oral sex. This infection often goes unnoticed because many infected individuals may not exhibit symptoms, yet it can lead to serious health issues if left untreated, such as pelvic inflammatory disease (PID) and infertility in both men and women.

In contrast, diabetes, though a serious health condition, is not transmitted through sexual contact; it is a metabolic disorder related to insulin and blood sugar levels. Influenza, a viral infection primarily affecting the respiratory system, spreads through respiratory droplets and is not classified as an STI. Hepatitis B is indeed sexually transmissible, but it is essential to recognize that Chlamydia is more prevalent as a common STI and is often highlighted in discussions about sexually transmitted infections due to its higher rates of infection among sexually active individuals.