## Core Concept
The corneal endothelium is a single layer of cells on the inner surface of the cornea, playing a crucial role in maintaining corneal clarity by regulating its hydration. Injury to the corneal endothelium can disrupt this function.

## Why the Correct Answer is Right
The human corneal endothelium has a limited capacity for regeneration. After injury, the endothelial cells can undergo **migration** and **proliferation** to cover the denuded area, but this process is limited. The endothelium can also undergo **compensation** by spreading and increasing in density to cover the damaged area, which helps in restoring the barrier function to some extent.

## Why Each Wrong Option is Incorrect
- **Option A:** This option is incorrect because it suggests no change or repair, which contradicts the known healing processes of the corneal endothelium.
- **Option B:** This option might suggest an incorrect or incomplete mechanism of healing, such as only proliferation without acknowledging the role of cell migration.
- **Option C:** While certain types of cells can regenerate effectively, the corneal endothelium in adults has a very limited ability to regenerate in the traditional sense (through cell division), making this option incorrect.

## Clinical Pearl / High-Yield Fact
A key point to remember is that the corneal endothelium's ability to heal is significantly reduced with age and in certain pathological conditions. Clinically, this is relevant because endothelial dysfunction can lead to corneal edema and vision loss, particularly after intraocular surgery or trauma.

## Correct Answer: D. Compensates by spreading.