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': 'Contact lens is best used in: \nSelect and explain. \nA. High myopia, B. Irregular astigmatism, C. Aphakia, D. Regular astigmatism', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. Irregular astigmatism', 'role': 'assistant'}]