This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Retina, Subject name: Ophthalmology
A young adult presents with night blindness and tubular vision. On examination, Intraocular Pressure was observed to be 18 mm and the anterior segment was unremarkable. Fundoscopy showed attenuation of arterioles and waxy pallor of the optic disc with bony corpuscles like spicules of pigmentation in mid peripheral retina. Ring scotomas were observed on perimetry. Which of the following is the most likely diagnosis: 
Select and explain. 
A. Pigmentary retinal dystrophy, B. Primary open angle glaucoma, C. Lattice degeneration of retina, D. Diabetic retinopathy
A: Pigmentary retinal dystrophy
Answer: A: Pigmentary retinal dystrophy 
Explanation: Ans. (a) Pigmentary Retinal DystrophyRef Kanski 7/e, p. 653The classical triad of arteriolar attenuation, bone spicule pigmentation and waxy disc pallor along with ..... Ring scotoma suggests the diagnosis to Typical Retinitis Pigmentosa or pigmentary Retinal Dystrophy.