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': 'Stain used to make the wetted area of filter paper strip more visible is \nSelect and explain. \nA. Eosin stain, B. Hematoxylin stain, C. Ninhydrin stain, D. Blue stain', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]