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': 'What is deposited in Kyser-Fleischer ring - \nSelect and explain. \nA. Copper, B. Lead, C. Mercury, D. Heme', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Kayser-FLeischer (KF) ring → Copper deposition in Chalcosis or Wilson’s disease\nFleischer ring → Deposition of iron and is a sign of keratoconus', 'role': 'assistant'}]