**Core Concept**
Reye's syndrome is a rare but serious condition that affects the liver and brain, typically occurring in children recovering from a viral infection. It is characterized by the accumulation of fatty deposits in the liver (steatosis) and inflammation of the brain (encephalitis).

**Why the Correct Answer is Right**
The histological hallmark of Reye's syndrome is the presence of microvesicular steatosis in the liver, where small lipid droplets accumulate in the hepatocytes. This is due to the impaired function of the mitochondria, leading to increased levels of fatty acids and their subsequent accumulation in the liver cells. The exact mechanism is not fully understood, but it is thought to involve the interaction between the viral infection and the use of aspirin, which may disrupt mitochondrial function and lead to the characteristic histological findings.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not accurately describe the histological finding associated with Reye's syndrome.
* **Option B:** This option is incorrect because it is not specific to Reye's syndrome and can be seen in other conditions as well.
* **Option C:** This option is incorrect because it does not accurately describe the histological finding associated with Reye's syndrome.

**Clinical Pearl / High-Yield Fact**
Reye's syndrome is a rare but serious condition that highlights the importance of avoiding aspirin use in children recovering from viral infections. It is essential to educate patients and families about this risk and to consider alternative medications for pain management.

**Correct Answer: D. Microvesicular steatosis.**