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: Ophthalmology
In the nasolacrimal duct, valve of Hasner is present at its: 
Select and explain. 
A. Upper end, B. Lower end, C. Middle, D. None of the above
B: Lower end
Answer: B: Lower end 
Explanation: Ans. Lower end