This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
Fundoscopy of a patient shows chalky white optic disc with well defined margins. Retinal vessels and surrounding Retina appears normal. Which of the following is the most likely diagnosis- 
Select and explain. 
A. Primary Optic Atrophy, B. Post-neuritic secondary optic atrophy, C. Glaucomatous optic atrophy, D. Consecutive optic atrophy
A: Primary Optic Atrophy
Answer: A: Primary Optic Atrophy 
Explanation: Chalky white optic disc with well defined margins along with normal retinal vessels and surrounding retina is typical of Primary Optic Atrophy.