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
Which is the most common oppounistic retinal infection associated with HIV 
Select and explain. 
A. CMV retinitis, B. VZV, C. Syphilictic retinitis, D. Herpes simplex
A: CMV retinitis
Answer: A: CMV retinitis 
Explanation: Cytomegalovirus (CMV) retinitis is a sight-threatening disease associated with AIDS (acquired immune deficiency syndrome) -- a serious disease of the immune system caused by infection with HIV (human immunodeficiency virus). In the past, about a quaer of active AIDS patients developed CMV retinitis. Ref ananthnarayana and panikers microbiology textbook 8/e