NOT a relation of sphenoid sinus:: (A) Optic nerve, (B) Mandibular nerve, (C) Maxillary nerve, (D) Vidian nerve
Answer is B. Structures related to sphenoid sinus are foramen rotundum (maxillary nerve), optic canal (optic nerve and ophthalmic artery), vidian canal (with nerve), internal carotid artery.
 Mandibular nerve is not related to sphenoid sinus.