This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Inflammatory Disorders, Subject name: Ophthalmology
Most common organism causing chorioretinitis in HIV is- 
Select and explain. 
A. CMV retinitis, B. Tocoplasma retinochoroiitis, C. Syphilitic retinitis, D. Pneumocystis carini
A: CMV retinitis
Answer: A: CMV retinitis 
Explanation: Ans. is 'a' i.e., CMV retinitis o "Cytomegalovirus (CMV) is the most common cause of chorioretinitis in patients who are HIV positive.