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': 'Best preservative for protozoal cysts is \nSelect and explain. \nA. 10 % formalin, B. Isopropyl alchol, C. HCL Solution, D. Naoh solution', 'role': 'user'}, {'content': 'Answer: A \nExplanation: 10 % formalin is ALL - purpose fixative used for preservation of morphology of helminth eggs, larvae, protozoan cysts and coccidian.', 'role': 'assistant'}]