**Core Concept**
Romanowsky stains, also known as Wright-Giemsa stains, are a class of supravital stains used in hematology to differentiate various cellular components in blood smears. They are particularly useful in identifying specific morphological features of red blood cells, white blood cells, and platelets.

**Why the Correct Answer is Right**
The correct answer involves identifying structures that are indeed visible on Romanowsky-stained blood smears. **Cabot rings** are ring-shaped inclusions within red blood cells, often associated with megaloblastic anemia. **Basophilic stippling** refers to the presence of small, blue-gray inclusions within red blood cells, typically seen in lead poisoning or other conditions affecting heme synthesis. **Howell-Jolly bodies** are small, round, blue inclusions within red blood cells, usually indicative of asplenia or hyposplenism. The Romanowsky stain is sensitive enough to detect these small inclusions, making it an effective tool for diagnosing various hematological disorders.

**Why Each Wrong Option is Incorrect**
**Option A:** Cabot rings are not unique to Romanowsky staining; they can be visualized using other stains like New Methylene Blue.
**Option B:** Basophilic stippling can also be detected using other stains like Prussian blue, but Romanowsky stain is more commonly used for this purpose.

**Clinical Pearl / High-Yield Fact**
When interpreting Romanowsky-stained blood smears, it's essential to consider the overall clinical context, as these stains can also reveal other abnormalities, such as platelet abnormalities, white blood cell morphology, and parasitic infections.

**✓ Correct Answer: D. All of the above**