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': 'Commonest cause for bilateral proptosis in children is - \nSelect and explain. \nA. Cavernous hamangioma, B. Chloroma, C. Fibrous histiocytoma, D. Rhabdomyosarcoma', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Most common cause of bilateral proptosis: In children : Neuroblastoma and leukemia (chloroma). In adults : Thyroid ophthalmopathy. Most common cause of unilateral proptosis: In children : Orbital cellulitis. In adults : Thyroid ophthalmopathy. Ref: A. K. Khurana 6thE pg404', 'role': 'assistant'}]