This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Physiology of nose, Subject name: ENT
Fronto-nasal duct opens into: 
Select and explain. 
A. Inferior meatus, B. Middle meatus, C. Superior meatus, D. Inferior turbinate
B: Middle meatus
Answer: B: Middle meatus 
Explanation: The Frontal sinus opens in the middle meatus through a duct known as fronto-nasal duct or frontal recess.