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': 'Bilateral proptosis is common in \nSelect and explain. \nA. Cavernous hemangioma, B. Rhabdomyosarcoma, C. A-V communications, D. Orbital cellulitis', 'role': 'user'}, {'content': 'Answer: C \nExplanation: C i.e. A-V communications Cavernous hemangioma, capillary hemangioma, dermoid cyst, rhabdomyosarcoma, fibrous histiocytoma, and orbital cellulitisQ mostly cause unilateral proptosis. AV communications eg carotid - cavernous fistula are usually unilateral but may become bilateral (contralateral) alsoQ.', 'role': 'assistant'}]