This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
[{'content': 'Which of these is not a tributary of cavernous sinus - \nSelect and explain. \nA. Sphenoparietal sinus, B. Superior petrosal sinus, C. Superficial middle cerebral vein, D. Inferior ophthalmic vein', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Superior petrosal sinus is a draining channel (not a tributary) of the cavernous sinus. \nTributaries (incoming channels) of the cavernous sinus\n\n\nSuperior ophthalmic vein\nA branch of an inferior ophthalmic vein or sometimes vein itself\nCentral vein of the retina (it may also drain into a superior ophthalmic vein)\nSuperficial middle cerebral vein\nInferior cerebral vein\nSphenoparietal sinus\nFrontal trunk of middle meningeal vein (it may also drain into pterygoid plexus or into sphenoparietal sinus)', 'role': 'assistant'}]