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': 'Keratoconus is seen in: March 2010 \nSelect and explain. \nA. Patau syndrome, B. Down syndrome, C. Turner syndrome, D. Weber syndrome', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B: Down syndrome', 'role': 'assistant'}]