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: Pathology
Acid mucin is best demonstrated by the stain ? 
Select and explain. 
A. Alcian blue, B. Periodic Acid Schiff (P.A.S.), C. Van Gieson, D. Reticulin
A: Alcian blue
Answer: A: Alcian blue 
Explanation: Ans. is 'a' i.e. Alacine blue