Which of the following statements is true?
A. Having one STI increases a person's risk for acquiring another one.
B. Sexually transmitted infections were largely unknown until roughly 200 years ago.
C. Doctors are required to report all cases of sexually transmitted infections to the federal government.
D. All of these are correct

B. Sexually transmitted infections were largely unknown until roughly 200 years ago.

Explanation:

Most sexually transmitted infections were largely unknown to the old medical communities. 200 years ago, it was also known about these diseases, neither how they were treated nor how most were contracted. Over time these diseases have been studied more deeply, this whole study combined with the advancement of technology has allowed us to currently have a vast knowledge about these diseases and the ways to avoid and treat them.

We can use as an example, the written account of a German soldier named Ulrich von Hutten, who contracted syphilis in the middle of 1509 and spent 10 years suffering from the disease without anyone knowing for sure what it was, nor how to treat it.