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': 'Hypovitaminosis D causes – \nSelect and explain. \nA. Zonular cataract, B. Blue – Dot cataract, C. Rosette cataract, D. Cupuliform cataract', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Hypocalcaemia (Hypoparathyroidism, hypovitaminosis D) causes zonular (lamellar) cataract.', 'role': 'assistant'}]