**Core Concept**
The patient's presentation with night blindness, tubular vision, and specific fundoscopic findings suggests a degenerative retinal disorder. The presence of ring scotomas on perimetry and characteristic retinal pigmentary changes points towards a particular type of retinal degeneration.

**Why the Correct Answer is Right**
The patient's symptoms and findings are consistent with **Retinitis Pigmentosa (RP)**, a group of genetic disorders characterized by progressive degeneration of the retina. The fundoscopic findings, including attenuation of arterioles, waxy pallor of the optic disc, and bone spicule pigmentation, are classic for RP. The presence of ring scotomas on perimetry is also typical, as patients with RP often have peripheral visual field loss that progresses to central vision loss.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is likely **Diabetic Retinopathy**, which would present with different fundoscopic findings, such as microaneurysms, hemorrhages, and neovascularization. While night blindness can occur in diabetes, the specific findings in this case are not typical for diabetic retinopathy.
* **Option B:** This option is likely **Central Serous Chorioretinopathy (CSCR)**, which would present with a distinct "blister" of fluid under the retina, often in the macula. The patient's symptoms and fundoscopic findings do not align with CSCR.
* **Option C:** This option is likely **Age-related Macular Degeneration (AMD)**, which would present with different fundoscopic findings, such as drusen or geographic atrophy, and would typically affect older adults rather than young adults.
* **Option D:** This option is likely **Uveitis**, which would present with inflammation of the uvea and would typically be associated with pain, redness, and light sensitivity. The patient's symptoms and fundoscopic findings do not align with uveitis.

**Clinical Pearl / High-Yield Fact**
Retinitis Pigmentosa is a group of disorders that can be inherited in an autosomal dominant, autosomal recessive, or X-linked pattern. It is essential to perform a thorough family history and genetic testing to determine the underlying cause of the patient's condition.

**Correct Answer:**
Retinitis Pigmentosa.