The overall number of cases of STIs is:

Choice A reason: According to the CDC, nearly half (46%) of all new STDs occur among people between the ages of 15-24¹. This age group also has the highest rates of chlamydia, gonorrhea, and syphilis infections compared to other age groups. Some factors that contribute to this high burden of STDs among young people are biological, behavioral, and social.

Choice B reason: This is incorrect. The age group of 51-60 years old has lower rates of STD infection than the age group of 15-24 years old. According to the CDC, the reported rates of chlamydia, gonorrhea, and syphilis among 51-60 year olds in 2020 were 59.8, 54.7, and 12.4 per 100,000 population, respectively. These rates are much lower than the rates among 15-24 year olds, which were 1,583.3, 1,021.9, and 45.5 per 100,000 population, respectively.

Choice C reason: This is incorrect. The age group of 25-35 years old has lower rates of STD infection than the age group of 15-24 years old. According to the CDC, the reported rates of chlamydia, gonorrhea, and syphilis among 25-35 year olds in 2020 were 1,017.9, 1,015.6, and 66.9 per 100,000 population, respectively. These rates are lower than the rates among 15-24 year olds, which were 1,583.3, 1,021.9, and 45.5 per 100,000 population, respectively.

Choice D reason: This is incorrect. The age group of 36-50 years old has lower rates of STD infection than the age group of 15-24 years old. According to the CDC, the reported rates of chlamydia, gonorrhea, and syphilis among 36-50 year olds in 2020 were 316.6, 337.9, and 27.9 per 100,000 population, respectively. These rates are lower than the rates among 15-24 year olds, which were 1,583.3, 1,021.9, and 45.5 per 100,000 population, respectively.

Choice A reason: Human papillomavirus is incorrect because it is not caused by a bacterium, but by a virus. It can cause genital warts and cervical cancer, but it cannot be cured with antibiotics.

Choice B reason: Gonorrhea is correct because it is caused by a bacterium called Neisseria gonorrhoeae, often produces no symptoms, but can be treated with antibiotics. If symptoms occur, they may include painful urination and discharge from the penis or vagina. If left untreated, the infection can result in more serious long-term problems, including infertility, pain, and joint problems.

Choice C reason: Herpes simplex virus is incorrect because it is not caused by a bacterium, but by a virus. It can cause genital herpes, which is marked by painful blisters and sores in the genital area. It cannot be cured with antibiotics, but antiviral medications can help reduce the frequency and severity of outbreaks.

Choice D reason: Cytomegalovirus is incorrect because it is not caused by a bacterium, but by a virus. It usually causes mild or no symptoms in healthy people, but can be serious in people with weakened immune systems or unborn babies. It cannot be cured with antibiotics, but antiviral medications can help treat the symptoms.