This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Diseases of orbit, Lids and lacrimal apparatus, Subject name: Ophthalmology
[{'content': 'All the following signs could result from infection with in the right cavernous sinus except- \nSelect and explain. \nA. Constricted pupil in response to light, B. Engorgement of the retinal veins upon ophthalmoscopic examination, C. Ptosis of the right eyelid, D. Right ophthalmoplegia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Cavernous sinus thrombosis *Patient develops severe pain in the eye and forehead of the involved side. *Conjunctiva is swollen and congested. *Proptosis *Ptosis (due to 3rd N.Palsy) *Dilated pupil (due to 3rd N involvement ) *Retinal veins shows congestion. *Papilloedema *Fundus may be normal Ref: Khurana 7th/e p.428', 'role': 'assistant'}]