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
Stain used to make the wetted area of filter paper strip more visible is 
Select and explain. 
A. Eosin stain, B. Hematoxylin stain, C. Ninhydrin stain, D. Blue stain
C: Ninhydrin stain
Answer: C: Ninhydrin stain 
Explanation: None