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': 'Commonest cause for bilateral proptosis children is: \nSelect and explain. \nA. Cavernous hamangioma, B. Chloroma, C. Fibrous histiocyloma, D. Rhabdomyosarcoma', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. Chloroma', 'role': 'assistant'}]