**Core Concept**
Horner-Trantas dots are small, white or yellowish spots found on the limbus of the eye in conditions associated with ocular inflammation, such as vernal keratoconjunctivitis (VKC) or trachoma.

**Why the Correct Answer is Right**
Horner-Trantas dots are thought to be accumulations of eosinophils, a type of white blood cell that plays a key role in the body's allergic response. In VKC, the presence of these dots is a hallmark of the disease and can be seen on the limbus, particularly in the 3-9 o'clock position. The exact mechanism behind their formation is not fully understood, but they are believed to be related to the immune system's response to allergens in the eye.

**Why Each Wrong Option is Incorrect**
**Option A:** Not a recognized condition associated with Horner-Trantas dots.
**Option B:** While conjunctivitis can have various presentations, Horner-Trantas dots are specific to VKC and trachoma.
**Option C:** Not a condition that typically presents with Horner-Trantas dots.

**Clinical Pearl / High-Yield Fact**
Horner-Trantas dots are an important diagnostic feature of VKC, and their presence can help differentiate this condition from other forms of conjunctivitis.

**Correct Answer:** D. Trachoma.