**Core Concept**
The notochord is a precursor to the vertebral column and central nervous system in the embryonic development of vertebrates. It is a flexible rod-like structure that provides axial support and is essential for the formation of the neural tube and the development of the vertebral column.

**Why the Correct Answer is Right**
The remnant of the notochord persists in the adult human body as the nucleus pulposus of the intervertebral discs. The nucleus pulposus is a soft, gel-like tissue that provides cushioning and shock-absorbing properties to the spine, allowing for flexibility and movement. The notochordal cells in the nucleus pulposus produce proteoglycans, which are essential for maintaining the water content and viscosity of the disc.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it refers to the chorda tympani, a nerve that carries taste fibers from the anterior two-thirds of the tongue and is not a remnant of the notochord.

**Option B:** This option is incorrect as it refers to the chorda vasculosa, a vascular structure that is not a remnant of the notochord.

**Option C:** This option is incorrect as it refers to the dorsal root ganglia, which are clusters of nerve cell bodies that are not a remnant of the notochord.

**Clinical Pearl / High-Yield Fact**
The nucleus pulposus is composed of notochordal cells, which produce proteoglycans that maintain the water content and viscosity of the disc. This is essential for the proper functioning of the intervertebral discs and the maintenance of spinal flexibility and movement.

**Correct Answer: D. Nucleus pulposus of intervertebral discs**