This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neuro Ophthalmology, Subject name: Ophthalmology
A chronic tobacco chewer came to OPD with diminution of vision. Which of the following nutritional supplement can be provided to him: 
Select and explain. 
A. Vitamin B1, B. Vitamin B2, C. Vitamin B6, D. Vitamin B12
D: Vitamin B12
Answer: D: Vitamin B12 
Explanation: Vitamin B12 is used for tobacco associated amblyopia. Tobacco associated amblyopia Seen in men doing heavy smoking, drinking and diet deficient in protein and vitamin B complex. Toxic agent involved is cyanide. B/L centrocecal scotomas are seen. Vitamin B12, 1000 microgram i.m injection weekly.