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
[{'content': 'A pregnant lady with AIDS complaint of diarrhea; on stool examination showing acid fast positive stain in cysts. She has: \nSelect and explain. \nA. Isospora belli, B. Microspora, C. Giardia, D. E. Histolytica', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Isospora belli', 'role': 'assistant'}]