**Core Concept**
Oil Red O stain is a lipophilic dye that detects neutral triglycerides and lipids in tissue sections. This histological stain is commonly used in pathology to identify adipocytes and lipid-laden cells in various conditions, including steatosis and lipid storage diseases.

**Why the Correct Answer is Right**
The Oil Red O stain selectively binds to the triglyceride molecules within the lipid droplets of adipocytes, highlighting them against a contrasting background. The high lipophilicity of the dye allows it to penetrate and bind to the hydrophobic lipid molecules, making it a reliable tool for detecting lipid accumulation in tissue samples.

**Why Each Wrong Option is Incorrect**
**Option A:** Sudan IV is another lipophilic dye, but it is primarily used to stain lipids in frozen sections and is not as commonly used as Oil Red O for paraffin-embedded tissue.
**Option B:** Hematoxylin and eosin (H&E) is a general-purpose stain used for histological examination, but it is not specific for detecting lipids in tissue.
**Option C:** Periodic acid-Schiff (PAS) is a staining method used to detect glycogen and other carbohydrates in tissue sections, not lipids.
**Option D:** Gomori's trichrome stain is used to differentiate collagen and other connective tissue elements from surrounding tissue, but it is not used for lipid detection.

**Clinical Pearl / High-Yield Fact**
When interpreting histological sections stained with Oil Red O, it's essential to consider the clinical context and differential diagnoses for lipid storage diseases, such as type IV hyperlipoproteinemia and abetalipoproteinemia.

**Correct Answer:** D. Sudan IV