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': 'Causes of anterior polar cataract – \nSelect and explain. \nA. Diabetes, B. Perforating corneal injury, C. Irradiation, D. Chalcosis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]