**Core Concept**
The question describes a clinical presentation of a young adult with night blindness, tubular vision, and characteristic fundoscopic findings. This presentation is suggestive of a specific retinal disorder that affects the peripheral retina, leading to visual field defects and characteristic changes in the mid-peripheral retina.

**Why the Correct Answer is Right**
The patient's symptoms and fundoscopic findings are consistent with a diagnosis of **Retinitis Pigmentosa (RP)**. RP is a group of genetic disorders that affect the peripheral retina, leading to progressive loss of rod photoreceptors. The characteristic fundoscopic findings in RP include attenuation of arterioles, waxy pallor of the optic disc, and bony corpuscles like spicules of pigmentation in the mid-peripheral retina. The presence of ring scotomas on perimetry further supports this diagnosis, as RP typically affects the peripheral visual field, leading to characteristic ring scotomas.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because **Leber Congenital Amaurosis (LCA)** typically presents in early childhood with severe visual impairment, whereas the patient in this scenario is a young adult with night blindness and tubular vision.

**Option B:** This option is incorrect because **Central Serous Retinopathy (CSR)** typically presents with a sudden onset of central visual loss, often with a "pseudohole" in the macula, whereas the patient in this scenario has night blindness and tubular vision with characteristic fundoscopic findings.

**Option C:** This option is incorrect because **Age-related Macular Degeneration (AMD)** typically presents with central visual loss and characteristic fundoscopic findings such as drusen and geographic atrophy, whereas the patient in this scenario has night blindness and tubular vision with characteristic peripheral retinal changes.

**Option D:** This option is incorrect because **Diabetic Retinopathy (DR)** typically presents with characteristic fundoscopic findings such as microaneurysms, hemorrhages, and hard exudates, whereas the patient in this scenario has night blindness and tubular vision with characteristic peripheral retinal changes.

**Clinical Pearl / High-Yield Fact**
Retinitis Pigmentosa is a group of genetic disorders that affect the peripheral retina, leading to progressive loss of rod photoreceptors and characteristic visual field defects. The characteristic fundoscopic findings in RP include attenuation of arterioles, waxy pallor of the optic disc, and bony corpuscles like spicules of pigmentation in the mid-peripheral retina.

**Correct Answer:** C.