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': 'Lens contain which antigen? \nSelect and explain. \nA. Sequestered antigens, B. Cross antigens, C. Heterophile antigens, D. Isoantigens', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Sequestered antigens', 'role': 'assistant'}]