**Core Concept**
The mother's positive HBsAg status indicates that she is a carrier of hepatitis B virus (HBV), which can be transmitted to the newborn during delivery. The goal is to prevent neonatal infection by administering a specific medication to the newborn.

**Why the Correct Answer is Right**
The correct answer is hepatitis B immune globulin (HBIG) in combination with the first dose of hepatitis B vaccine. This combination is recommended for newborns born to HBsAg-positive mothers to provide immediate passive immunity against HBV and initiate active immunity through vaccination. HBIG contains antibodies against HBV, which can neutralize the virus in the newborn, while the hepatitis B vaccine stimulates the production of antibodies against the virus. This dual approach significantly reduces the risk of neonatal HBV infection.

**Why Each Wrong Option is Incorrect**
* **Option A:** The mother's HBsAg status is not relevant to the administration of this medication. This option is incorrect because it does not address the specific risk of HBV transmission to the newborn.
* **Option B:** This medication is not typically used in the context of preventing neonatal HBV infection. It may be used for other conditions, but it is not the correct choice in this scenario.
* **Option D:** While this medication is sometimes used in the management of HBV infection, it is not the correct choice for preventing neonatal infection in this scenario.

**Clinical Pearl / High-Yield Fact**
Newborns born to HBsAg-positive mothers should receive HBIG and the first dose of hepatitis B vaccine within 12 hours of birth to prevent neonatal HBV infection.

**Correct Answer:** C. HBIG and hepatitis B vaccine.