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': 'Cryptosporidium cyst identified by which stain in stool sample? \nSelect and explain. \nA. PAS, B. H and E, C. Giemsa, D. Acid fast stain', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. d. Acid fast stain', 'role': 'assistant'}]