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
CMV retinitis in HIV patient is seen when CD4 count is - 
Select and explain. 
A. <50, B. <100, C. <200, D. <150
A: <50
Answer: A: <50 
Explanation: 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