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': 'Basic lesion in tobacco amblyopia is: \nSelect and explain. \nA. Degeneration of ganglion cells especially of macular region, B. Degeneration of foveal cones, C. Ischaemia of optic nerve fibres, D. All of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Degeneration of ganglion cells especially of macular region', 'role': 'assistant'}]