This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
The most common organism amongst the following that causes acute meningitis in an AIDS patient is - 
Select and explain. 
A. Streptococcus pneumoniae, B. Streptococcus agalactiae, C. Cryptococcus neoformans, D. Listeria monocytogenes
C: Cryptococcus neoformans
Answer: C: Cryptococcus neoformans 
Explanation: Cryptococcosis is the predominant cause of fatal fungal infection and causes acute... meningitis in patients with AIDS.
It may occur most common when CD4+ count falls below 200 cells/mm3.
The extra pulmonary cryptococcosis is one of the AIDS defining diseases.