This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nose and paranasal sinuses, Subject name: ENT
[{'content': 'Cavernous sinus thrombosis following sinusitis results in all of the following signs except: \nSelect and explain. \nA. Constricted pupil in response to light, B. Engorgement of retinal veins upon ophthalmoscopic examination, C. Ptosis of eyelid, D. Ophthalmoplegia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ptosis and ophthalmoplegia occur in cavernous sinus thrombosis due to involvement of III and IV and V cranial nerves. Retinal vessels are also engorged but pupils are fixed and dilated,due to involvement of III nerve and sympathetic plexus. Ref Dhingra 5/e,p 214.', 'role': 'assistant'}]