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': 'Cavernous sinus thrombosis is due infection of \nSelect and explain. \nA. Pterygoid plexus, B. Submental space, C. Maxillary sinus, D. Submandibular space', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Pterygoid plexus and the facial vein form the 2 major sources which carry the infections from the danger area of face to the cavernous sinus.', 'role': 'assistant'}]