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': 'Sunflower cataract is due to deposition of: \nSelect and explain. \nA. Cu, B. Zn, C. Fe, D. Ca', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A i.e. Cu Cataract Snowflake cataract: DM Rossette cataract: Trauma Christmas tree pattern: Myotonic dystrophy Sunflower cataract: Wilsons disease Oil drop cataract: Galactosemia', 'role': 'assistant'}]