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
Vitamin B 12  deficiency is likely to cause - 
Select and explain. 
A. Bitemporal hemianopia, B. Binasal hemianopia, C. Heteronymous hemianopia, D. Centrocecal scotoma
D: Centrocecal scotoma
Answer: D: Centrocecal scotoma 
Explanation: The predominant cause of nutritional optic neuritis is thought to be deficiency of B - complex vitamins, particularly thiamin (vitamin B1) and cyanocobalamin (Vitamin B12). Deficiency of pyridoxin (vitamin B6), niacin (vitamin B3), riboflavin (vitamin B2), and / or folic acid also seems to play a role.
Most common visual field defect is central or centrocaecal scotoma.