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': 'Which is the commonest cause of occular morbidity in the community \nSelect and explain. \nA. Cataract, B. Refractive error, C. Occular injury, D. Vitamin A deficiency', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Refractory Error', 'role': 'assistant'}]