This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Virology, Subject name: Microbiology
CMV retinitis in HIV occurs when teh CD4 counts falls below - 
Select and explain. 
A. 50, B. 100, C. 200, D. 150
B: 100
Answer: B: 100 
Explanation: CD4 count<100 cells/mm3 REF:<\p> MICROBIOLOGY ANANTHA NARAYANAN NINTH EDITION PAGE.473 case-3