This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ear, Subject name: ENT
[{'content': 'Infection within the right cavernous sinus results in the following signs except: \nSelect and explain. \nA. Constricted pupils in response to light, B. Engorgement of retinal veins, C. Ptosis of right eyelid, D. Right ophthalmoplegia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: (a) Constricted pupils in response to light (Ref. Cummings, 6th ed., 174)In cavernous sinus thrombosis pupils are dilated and fixed due to the involvement of 3rd nerve and stimulation of sympathetic plexus.', 'role': 'assistant'}]