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
[{'content': 'Vitamin used for treating toxic ambylopia: March 2012 \nSelect and explain. \nA. Hydroxycobalamine, B. Vitamin B1, C. Vitamin B6, D. Vitamin B3', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans: A i.e. Hydroxycobalamine Improvement in toxic amblyopias/ tobacco induced optic neuropathy may be hastened by intramuscular injections of 1000 microgram hydroxycobalamine', 'role': 'assistant'}]