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: Surgery
Which of the following venous sinuses is more likely to be affected with thrombosis in chronic otitis media and  mastoiditis? 
Select and explain. 
A. Cavernous, B. Inter-Cavernous, C. Sigmoid, D. Superior petrosal
C: Sigmoid
Answer: C: Sigmoid 
Explanation: None