This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neuroanatomy, Subject name: Anatomy
[{'content': 'Angular vein infection causes thrombosis in: \nSelect and explain. \nA. Cavernous sinus, B. Suprasaggital sinus, C. Transverse sinus, D. Inferior petrosal sinus', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. A Cavernous sinusRef: Gray's Anatomy, 40th ed. Ch; 29* The upper most segment of the facial vein, above its junction with the superior labial vein, is also called the angular vein.* Any infection of the mouth or face can spread via the angular veins to the cavernous sinuses resulting in thrombosis.", 'role': 'assistant'}]