This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Histo Pathology, Subject name: Pathology
All of the following stains are used for fat except? 
Select and explain. 
A. Oil red O, B. Congo reds, C. Sudan black, D. Osmium tetroxide
B: Congo reds
Answer: B: Congo reds 
Explanation: Ans. is 'b' i.e., Congo red * Congo red is not used in lipid staining. It is used in the staining of amyloid protein.* Stain used for lipids (fatty acids)are Oil red O, Osmium tetroxide, sudan black and sudan III & IV.