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': 'Pulsatile proptosis is a feature of - \nSelect and explain. \nA. Orbital varix, B. Retinoblastoma, C. Coico-cavernous fistula, D. Covernous sinus thrombosis', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Pulsatile proptosis is seen in caroticocavernous fistula and saccular aneurysm of ophthalmic aery.it also occurs due to transmitted cerebral pulsations in conditions associated with deficient orbital roof. Ref .ak khurana 6th edition pg no 404 REF IMG', 'role': 'assistant'}]