This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Medicine
[{'content': 'CMV retinitis in HIV patient is seen when CD4 count is - \nSelect and explain. \nA. <50, B. <100, C. <200, D. <150', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Cytomegalovirus retinitis (CMVR) is an AIDS-defining diagnosis, and typically occurs when CD4 counts fall below 50 cells per ml . Ref - Davidson 23rd edition pg 340', 'role': 'assistant'}]