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: Medicine
[{'content': 'In ethambutol toxicity defect is seen in - \nSelect and explain. \nA. Red vision, B. Green vision, C. Yellow vision, D. Blue vision', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]