**Core Concept**
Retinal detachment is a condition where the sensory retina separates from the underlying retinal pigment epithelium, leading to vision loss. This separation occurs due to various factors, including trauma, inflammation, or age-related degeneration. The sensory retina is composed of the nerve fiber layer, ganglion cell layer, inner plexiform layer, inner nuclear layer, outer plexiform layer, and photoreceptor layer.

**Why the Correct Answer is Right**
The sensory retina detaches from the retinal pigment epithelium, which is the layer responsible for phagocytosing shed photoreceptor outer segments. The sensory retina contains the photoreceptors (rods and cones) and the bipolar cells that transmit visual information to the ganglion cells. The detachment of the sensory retina from the retinal pigment epithelium disrupts this visual pathway, leading to vision loss. The retinal pigment epithelium is the layer that remains attached to the underlying choroid.

**Why Each Wrong Option is Incorrect**
**Option B:** The pigmentary retina, also known as the retinal pigment epithelium, is the layer that remains attached to the choroid in retinal detachment. It is not the layer that detaches.
**Option C:** The inner nuclear layer is a part of the sensory retina but is not the layer that detaches in retinal detachment.
**Option D:** The outer plexiform layer is also a part of the sensory retina and is not the layer that detaches in retinal detachment.

**Clinical Pearl / High-Yield Fact**
Retinal detachment is a medical emergency that requires prompt treatment to prevent permanent vision loss. Early symptoms may include flashes of light, floaters, or a curtain descending over the visual field.

**Correct Answer:**
✓ Correct Answer: A. Sensory retina