**Core Concept**
Herpes Zoster Ophthalmicus (HZO) is a viral infection caused by the reactivation of varicella-zoster virus in the ophthalmic division of the trigeminal nerve (V1). The virus affects the nerve cells of the eye and surrounding areas, leading to inflammation and rash.

**Why the Correct Answer is Right**
Herpes Zoster Ophthalmicus primarily affects the ophthalmic division of the trigeminal nerve (V1), which is responsible for sensation in the face, specifically around the eye, including the forehead, nose, and eyelids. The virus causes inflammation and damage to the nerve cells, leading to the characteristic symptoms of HZO. The correct answer is the nerve least likely to be involved in HZO.

**Why Each Wrong Option is Incorrect**
* **Option A:** The ophthalmic division of the trigeminal nerve (V1) is the primary nerve involved in HZO, making this option incorrect.
* **Option B:** The maxillary division of the trigeminal nerve (V2) is not primarily involved in HZO, but it is still a part of the trigeminal nerve and can be affected in some cases.
* **Option C:** The mandibular division of the trigeminal nerve (V3) is not typically involved in HZO, as it supplies sensation to the lower face and jaw.
* **Option D:** The facial nerve (VII) is responsible for controlling facial expressions and taste, and is not primarily involved in HZO.

**Clinical Pearl / High-Yield Fact**
The varicella-zoster virus can remain dormant in the nerve cells of the trigeminal nerve for years after a chickenpox infection, and can be reactivated later in life, causing HZO.

**Correct Answer:** C.