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: Ophthalmology
[{'content': 'All the following signs could result from infection within 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: A i.e. Constricted pupil in response to light', 'role': 'assistant'}]