This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: parasitology, Subject name: Microbiology
A 42yr old female with HIV is frequently suffering from diarrhoea despite treatment with HAA. Which of the following organisms can cause diarrhoea in HIV patients? 
Select and explain. 
A. Cryptosporidium, B. Microsporidia, C. Isospora, D. All the above
D: All the above
Answer: D: All the above 
Explanation: All the organisms can produce diarrhoea in HIV patients due to impaired t cell-mediated immunity Ref: D.R. Arora. Medical parasitology 4th ed pg. 239