**Core Concept**
The question is testing the knowledge of post-exposure prophylaxis (PEP) for HIV, which is an emergency medication taken after potential exposure to HIV to prevent infection. PEP involves a combination of antiretroviral drugs to suppress the virus and prevent it from establishing a permanent infection.

**Why the Correct Answer is Right**
The correct answer involves a combination of antiretroviral drugs that are effective in suppressing HIV replication. The most commonly used regimen for PEP includes two nucleoside reverse transcriptase inhibitors (NRTIs) and one protease inhibitor (PI). This combination is chosen because it has a synergistic effect in suppressing HIV replication and preventing the virus from developing resistance. The most commonly used combination is Tenofovir (an NRTI) + Emtricitabine (an NRTI) + Ritonavir-boosted Atazanavir (a PI).

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not include a combination of antiretroviral drugs. Monotherapy is not an effective approach for PEP.
* **Option B:** This option is incorrect because it does not include a protease inhibitor, which is a critical component of PEP.
* **Option D:** This option is incorrect because it includes a combination of antiretroviral drugs, but the specific regimen is not commonly used for PEP.

**Clinical Pearl / High-Yield Fact**
The key to successful PEP is prompt initiation, within 72 hours of potential exposure. The sooner PEP is started, the more effective it is in preventing HIV infection.

**Correct Answer: C. Tenofovir + Emtricitabine + Ritonavir-boosted Atazanavir**