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': 'Acquired colour blindness is due to \nSelect and explain. \nA. Increased sclerosis of the crystalline lens, B. Transient failure of retinal circulation, C. Occlusion of short posterior ciliary arteries, D. Non- Inflammatory edema of optic disc', 'role': 'user'}, {'content': 'Answer: A \nExplanation: May occurs in old age due to increased sclerosis of crystalline lens.\nMay follow damage to macula or optic nerve.', 'role': 'assistant'}]