**Core Concept**
The underlying principle being tested is the importance of early identification of HIV infection in pregnant women to prevent mother-to-child transmission (MTCT) of HIV. This is a critical aspect of maternal and child health, as it can significantly reduce the risk of HIV transmission to the infant.

**Why the Correct Answer is Right**
Early identification of HIV infection in pregnant women is crucial because it allows for timely initiation of antiretroviral therapy (ART) to suppress viral replication. This, in turn, reduces the risk of MTCT of HIV. Studies have shown that ART can significantly decrease the risk of HIV transmission to the infant from 25-30% in the absence of treatment to less than 2% with effective ART. The Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) recommend that all pregnant women be tested for HIV and receive ART if they are infected.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because while HIV testing is crucial, it is not the most important reason for early identification of HIV infection in pregnant women. Other factors, such as access to care and treatment, are also important but not as critical as preventing MTCT of HIV.

**Option B:** This option is incorrect because while HIV testing can identify women with undiagnosed HIV infection, it does not address the issue of MTCT of HIV. Other interventions, such as ART and safe delivery practices, are also necessary to prevent HIV transmission to the infant.

**Option C:** This option is incorrect because while HIV testing can identify women with HIV infection, it does not address the issue of MTCT of HIV. Other interventions, such as ART and safe delivery practices, are also necessary to prevent HIV transmission to the infant.

**Option D:** This option is incorrect because while HIV testing can identify women with HIV infection, it does not address the issue of MTCT of HIV. Other interventions, such as ART and safe delivery practices, are also necessary to prevent HIV transmission to the infant.

**Clinical Pearl / High-Yield Fact**
The "Option A" is incorrect because routine HIV testing is a critical preventive measure, but the primary goal is to prevent MTCT of HIV, not just to identify HIV-infected women.

**Correct Answer:** C. Reduced risk of mother-to-child transmission of HIV.