**Core Concept**
The lens of the eye develops from ectodermal cells, specifically from the surface ectoderm, which invaginates to form the lens pit and eventually differentiates into lens fibers and epithelial cells. This process is a critical aspect of embryonic development, leading to the formation of a functional lens in the adult eye.

**Why the Correct Answer is Right**
During embryonic development, the surface ectoderm overlying the optic vesicle invaginates to form the lens pit. As the pit deepens, it elongates and eventually pinches off from the surface ectoderm to form the lens vesicle. The lens vesicle then undergoes a series of complex cellular and molecular changes, including differentiation of lens fibers and epithelial cells, to form the mature lens of the eye. The lens fibers, which are formed from the lens epithelial cells, are responsible for the refractive power of the lens.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the lens does not develop from the mesoderm, which is a different germ layer involved in the formation of connective tissue, muscles, and other structures.
**Option B:** This option is incorrect because the lens does not develop from the neural crest, which is a group of cells that migrate from the ectoderm to form various structures, including cranial nerves and parts of the face.
**Option C:** This option is incorrect because the lens does not develop from the endoderm, which is a different germ layer involved in the formation of internal organs such as the gut and respiratory system.

**Clinical Pearl / High-Yield Fact**
The lens of the eye is a unique tissue that is capable of regeneration, but only in the context of embryonic development. In adults, the lens is unable to regenerate, and any damage to the lens fibers or epithelial cells can lead to permanent vision loss.

**Correct Answer:** C. Surface ectoderm.