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: Physiology
Valve of Hasner is present at 
Select and explain. 
A. Stensons duct, B. Common bile duct, C. Naso lacrimal duct, D. Maxillary Sinus
C: Naso lacrimal duct
Answer: C: Naso lacrimal duct 
Explanation: None