**Core Concept**
In chronic viral hepatitis, grading and staging are key components of histological assessment. Grading evaluates the severity of hepatocellular injury, primarily based on the extent of necrosis and inflammatory activity, while staging reflects the degree of fibrosis and architectural disruption.

**Why the Correct Answer is Right**
Grading in chronic viral hepatitis specifically refers to the degree of hepatocyte necrosis and inflammatory cell infiltration. This is assessed under the histological microscope and is crucial for determining disease severity and predicting prognosis. The American Association for the Study of Liver Diseases (AASLD) classification system uses grading to quantify active injury, with higher grades indicating more severe damage. This directly correlates with clinical outcomes and treatment decisions.

**Why Each Wrong Option is Incorrect**
Option A: Hepatitis A is typically acute and self-limiting; it does not commonly cause chronic infection, especially in children.
Option B: While morphological classification exists, the terms "chronic active" and "chronic persistent" are outdated or less used in current guidelines; modern classification emphasizes grading and staging.
Option C: Fatty change (steatosis) is common in Hepatitis C but is not pathognomonic—many other conditions (e.g., NAFLD, diabetes) also show steatosis.

**Clinical Pearl / High-Yield Fact**
Remember: Grading = necrosis and inflammation; Staging = fibrosis and architectural distortion. Never confuse the two—grading reflects injury, staging reflects scarring.

✓ Correct Answer: D. Grading refers to the extent of necrosis and inflammations