**Core Concept**
The question is testing the understanding of viral hepatitis, specifically the indicators of active multiplication of hepatitis B virus (HBV). HBV is a DNA virus that replicates in the liver cells of infected individuals, leading to various clinical manifestations.

**Why the Correct Answer is Right**
The correct indicators of active multiplication of HBV include elevated liver enzymes (such as alanine transaminase (ALT) and aspartate transaminase (AST)), positive HBV DNA polymerase activity, and the presence of HBV antigens in the blood. These markers indicate that the virus is actively replicating and causing liver damage. **HBV DNA polymerase** is a key enzyme involved in viral replication, and its presence or activity is a strong indicator of active viral multiplication.

**Why Each Wrong Option is Incorrect**
**Option A:** Elevated bilirubin levels may be a result of liver damage, but they are not specific indicators of active HBV multiplication.
**Option B:** The presence of HBV antibodies (such as HBsAb and HBcAb) indicates past or current infection, but they do not directly indicate active viral multiplication.
**Option C:** Leukocytosis may be a non-specific response to infection or inflammation, but it is not a specific indicator of active HBV multiplication.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that HBV DNA polymerase activity is a sensitive marker of active viral replication, and its measurement can help guide antiviral therapy.

**Correct Answer: D. Elevated liver enzymes, positive HBV DNA polymerase activity, and the presence of HBV antigens in the blood.**