**Core Concept**
Angular conjunctivitis refers to an inflammatory condition of the conjunctiva at the medial and lateral canthi, often presenting with symptoms of redness, discharge, and crusting. It is typically caused by an infectious agent.

**Why the Correct Answer is Right**
Angular conjunctivitis is commonly caused by Chlamydia trachomatis, a bacterium that also causes trachoma. The disease is often transmitted through close personal contact or contaminated fomites. The pathogenesis involves the adherence of the bacteria to the conjunctival epithelial cells, leading to an inflammatory response and subsequent symptoms.

**Why Each Wrong Option is Incorrect**
**Option A:** While Haemophilus influenzae can cause conjunctivitis, it is not the primary cause of angular conjunctivitis.
**Option B:** Staphylococcus aureus can cause conjunctivitis, but it is more commonly associated with blepharitis than angular conjunctivitis.
**Option C:** Moraxella lacunata can cause conjunctivitis, but it is not the primary cause of angular conjunctivitis.

**Clinical Pearl / High-Yield Fact**
Angular conjunctivitis is often associated with poor personal hygiene and is more common in individuals with compromised immune systems.

**Correct Answer: C. Moraxella lacunata**