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': 'True about anatomy of adult cornea: \nSelect and explain. \nA. Horizontal diameter is 12 mm, B. Horizontal diameter is 10 mm, C. In megalocornea diameter is >12 mm, D. Veical diameter> Horizontal diameter', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Horizontal diameter is 12 mm', 'role': 'assistant'}]