A. Routine prenatal HIV screening is recommended for all pregnant women, regardless of identified risk factors. Universal testing helps identify undiagnosed HIV early, allowing for timely antiretroviral therapy, which significantly reduces the risk of maternal-to-child transmission. This approach avoids missed diagnoses that can occur when testing is based only on perceived risk. B. Women with a history of STIs are at increased risk for HIV and should be tested; however, limiting testing only to this group would miss many cases. Therefore, this option is incomplete and not the most appropriate answer. C. Having multiple sexual partners increases the risk for HIV infection, but prenatal HIV testing is not limited to women with this risk factor. Universal screening is recommended instead. D. Even women who are monogamous may be at risk if their partner is infected or has other risk factors. For this reason, monogamy does not eliminate the need for prenatal HIV testing.