**Core Concept**
Stem cells in the cornea are responsible for maintaining the epithelial layer's integrity and transparency. They play a crucial role in wound healing and corneal homeostasis. The corneal stem cells are located in the limbal region, which is the border between the cornea and the sclera.

**Why the Correct Answer is Right**
The limbal stem cells are found in the basal layer of the limbal epithelium. They are responsible for producing new corneal epithelial cells through a process called asymmetric cell division. This process allows the stem cells to self-renew while also differentiating into new epithelial cells. The limbal stem cells are essential for maintaining the cornea's clarity and preventing vision loss.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because stem cells are not present in the corneal stroma, which is the middle layer of the cornea composed of collagen and keratocytes.
**Option B:** This option is incorrect because stem cells are not present in the corneal endothelium, which is the innermost layer of the cornea responsible for maintaining corneal deturgescence.
**Option C:** This option is incorrect because stem cells are not present in the corneal epithelium itself, but rather in the limbal region adjacent to it.

**Clinical Pearl / High-Yield Fact**
The limbal stem cells are sensitive to chemical and thermal injuries, which can lead to corneal ulcers and vision loss. Therefore, protecting the limbal region during surgeries and treatments is crucial for maintaining corneal health.

**Correct Answer:** C. The limbal region.