This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ocular trauma , Subject name: Ophthalmology
[{'content': 'What is deposited in Kayser-Fleischer ring - \nSelect and explain. \nA. Copper, B. Lead, C. Mercury, D. Iron', 'role': 'user'}, {'content': "Answer: A \nExplanation: It is a golden brown ring which occurs due to deposition of copper under peripheral pas of the Descemet's membrane of the cornea. Sunflower cataract-Deposition of copper under the posterior capsule of the lens. It is brilliant golden green in colour and arranged like the petals of a sunflower. Ref: Parsons' 22nd edition , page no.396", 'role': 'assistant'}]