This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: miscellaneous, Subject name: Pathology
Stain not used for lipid - 
Select and explain. 
A. Oil red, B. Congo red, C. Sudan III, D. Sudan black
B: Congo red
Answer: B: Congo red 
Explanation: Special stains for fat: Frozen sections stained with Sudan IV or Oil Red-O give an orange-red color to the fat. Osmic acid gives a black color.