This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Brainstem lesions and blood supply of CNS, Subject name: Anatomy
Cavernous sinus receives blood from - 
Select and explain. 
A. Superior ophthalmic vein, B. Superior petrosal sinus, C. Inferior petrosal sinus, D. Basilar plexus of veins
A: Superior ophthalmic vein
Answer: A: Superior ophthalmic vein 
Explanation: TRIBUTARIES OF CAVERNOUS SINUS I. FROM ORBIT 1. Superior ophthalmic vein (mostly)- bidirectional, can drain septic emboli into cavernous sinus leading to thrombosis 2. Inferior ophthalmic vein 3. Central vein of the retina II. FROM BRAIN 1. Superficial middle cerebral vein 2. Inferior cerebral veins from temporal lobe III. FROM MENINGES 1. Sphenoparietal sinus (drains meninges) DRAINING CHANNELS 1. Superior petrosal sinus 2. Inferior petrosal sinus 3. Emissary vein to pterygoid venous plexus.