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': 'The special stain used for treponema pallidum is \nSelect and explain. \nA. Giemsa staining, B. Gram staining, C. Fontanna silver, D. Ziel Neelson', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]