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
Method used for acid fast staining ? 
Select and explain. 
A. Robeson's method, B. Ziehl Neelsen, C. Silver imprignation method, D. Dark ground illumination
B: Ziehl Neelsen
Answer: B: Ziehl Neelsen 
Explanation: Ans. is 'b' i.e., Ziehl Neelsen Acid fast staining After staining with aniline dye, acid fast organisms resist decolourisation with acids. Method most commonly used is modified Ziehl Neelsen.