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': 'In a patient with AIDS, chorioretinitis is typically caused by – \nSelect and explain. \nA. Cytomegalovirus, B. Toxoplasma gondii, C. Cryptococcus neoformans, D. Histoplasma capsulatum', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The most common cause of chorioretinitis in AIDS is CMV.', 'role': 'assistant'}]