This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anti Microbial, Subject name: Pharmacology
[{'content': 'Antitubercular drug causing ophthalmic toxicity is: \nSelect and explain. \nA. Isoniazid, B. Rifampicin, C. Ethambutol, D. None of above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans, C EthambutolOptic neuritis due to ethambutol:* Reversible* Loss of red green color discrimination* Central scotomasExtra Edge points:Rifabutin and Rifampin can also orange tan discoloration of tears and contact lenses.', 'role': 'assistant'}]