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
All of the following are incoming tributaries of cavernous sinus except 
Select and explain. 
A. Superior ophthalmic vein, B. Superficial middle cerebral vein, C. Superior petrosal vein, D. Inferior cerebral vein
C: Superior petrosal vein
Answer: C: Superior petrosal vein 
Explanation: Superior petrosal vein is outgoing channel of cavernous sinus.