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': "WHO definition of blindness in addition to visual acuity of less than 3/60 (Snellen's) also includes a visual field in the better eye equal to or less than: \nSelect and explain. \nA. 5deg, B. 10deg, C. 15deg, D. 3deg", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. 5deg', 'role': 'assistant'}]