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: ENT
Most comon cause of obstruction in atrophic rhinitis is 
Select and explain. 
A. Excessive formation of crust, B. Polyp, C. Synechiae, D. Hypertrophy of turbinate
A: Excessive formation of crust
Answer: A: Excessive formation of crust 
Explanation: None