**Core Concept**
Epidemic hemorrhagic conjunctivitis (EHC) is a highly contagious and acute ocular infection characterized by sudden onset of conjunctival inflammation, hemorrhage, and sometimes corneal involvement. The condition is often associated with viral etiology, particularly enteroviruses.

**Why the Correct Answer is Right**
The correct answer is Coxsackie virus A24 variant (CVA24v), a serotype of the enterovirus, responsible for the majority of EHC outbreaks worldwide. This virus primarily infects the conjunctiva, leading to the characteristic symptoms of EHC, including conjunctival hemorrhage, edema, and sometimes corneal involvement. The virus is highly contagious and can spread through direct contact with an infected individual or contaminated surfaces.

**Why Each Wrong Option is Incorrect**
**Option A:** (Incorrect) Adenovirus can cause conjunctivitis, but it is not typically associated with the hemorrhagic form of EHC.
**Option B:** (Incorrect) Herpes simplex virus can cause ocular infections, but it is not the primary cause of EHC.
**Option C:** (Incorrect) Chlamydia trachomatis is a common cause of trachoma, a chronic conjunctival infection, but not EHC.

**Clinical Pearl / High-Yield Fact**
Coxsackie virus A24 variant (CVA24v) is a highly contagious and specific cause of EHC, often leading to outbreaks in crowded areas.

**Correct Answer:** C. Coxsackie virus A24 variant (CVA24v)