**Core Concept**
Inclusion conjunctivitis is a type of conjunctivitis caused by the reactivation of latent herpes simplex virus (HSV) in the trigeminal ganglion. This leads to the production of viral particles that travel through the ophthalmic branch of the trigeminal nerve to the eye, causing inflammation of the conjunctiva.

**Why the Correct Answer is Right**
The correct answer is caused by the reactivation of HSV, which is a member of the herpesvirus family. This reactivation occurs due to factors such as stress, UV light, or immunosuppression. Once the virus reactivates, it travels to the eye through the ophthalmic branch of the trigeminal nerve, where it causes inflammation of the conjunctiva and leads to the characteristic symptoms of inclusion conjunctivitis, including pain, redness, and the presence of dendritic ulcers.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because inclusion conjunctivitis is not caused by chlamydial infection, which is a common cause of other types of conjunctivitis.
**Option B:** This option is incorrect because varicella-zoster virus is the causative agent of herpes zoster (shingles), not inclusion conjunctivitis.
**Option C:** This option is incorrect because adenovirus is a common cause of epidemic keratoconjunctivitis, not inclusion conjunctivitis.

**Clinical Pearl / High-Yield Fact**
A key clinical correlation to remember is that patients with inclusion conjunctivitis often have a history of recurrent herpes labialis (cold sores) or genital herpes, indicating a propensity for HSV reactivation.

**Correct Answer: B. Varicella-zoster virus**