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: Mucin is produced by epithelial cells of mucous membrane & mucous glands, as well as by some connective tissues
Stains for mucin

Mucicarmine
Alcian blue.

Note :- Epithelial cell mucin stains positively with periodic acid-Schiff (PAS), while connective tissue mucin does not.