This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nose and paranasal sinuses, Subject name: ENT
Frontonasal duct opens into: 
Select and explain. 
A. Inferior meatus, B. Middle meatus, C. Superior meatus, D. Inferior meatus
B: Middle meatus
Answer: B: Middle meatus 
Explanation: The frontonasal duct is a communication between the frontal air sinuses and their corresponding nasal cavity. The duct is lined by mucous membrane. The duct empties into the nasal cavity middle nasal meatus through the infundibulum of the semilunar hiatus. Ref: Dhingra 6th edition, page 136.