Location Hasner's of valve-: (A) Opening of nasolacrimal duct, (B) Sphenoidal sinus opening, (C) Frontal sinus opening, (D) Ethmoidal sinus opening
Answer is A. Ans, is 'a' i.e., Opening of nasolacrimal duct o Nasolacrimal duct opens into inferior meatus and is closed by a mucosal flap called Hasner's valve.