**Core Concept**
The crystalline lens in the eye develops from the ectoderm, specifically from the surface ectoderm that invaginates to form the lens pit during embryonic development. This process is a critical aspect of eye morphogenesis.

**Why the Correct Answer is Right**
During embryonic development, the surface ectoderm covers the optic vesicle, which eventually invaginates to form the lens pit. The lens pit then undergoes a process called delamination, where the lens placode separates from the surface ectoderm and invaginates further to form the lens vesicle. The lens vesicle eventually differentiates into the crystalline lens, which is a critical component of the eye's refractive system.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the crystalline lens does not develop from the mesoderm, which gives rise to structures such as the sclera, choroid, and ciliary body.
* **Option B:** This option is incorrect because the retina develops from the neuroectoderm, specifically from the optic vesicle, but not from the surface ectoderm that gives rise to the crystalline lens.
* **Option C:** This option is incorrect because the vitreous body develops from the neural ectoderm, specifically from the optic cup, but not from the surface ectoderm that gives rise to the crystalline lens.

**Clinical Pearl / High-Yield Fact**
The crystalline lens is a unique structure that is capable of changing shape to focus light on the retina, a process known as accommodation. This is made possible by the lens's ability to change its refractive index in response to changes in the surrounding environment, allowing for clear vision at different distances.

**Correct Answer:** D.