This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Tumors, Subject name: Ophthalmology
[{'content': 'The most commonly seen primary orbital tumour in children is \nSelect and explain. \nA. Optic nerve sheath meningioma, B. Retinoblastoma, C. Rhabdomyosarcoma, D. Glioma of optic nerve', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Rhabdomyosarcoma It is a highly malignant tumour of the orbit arising from the extraocular muscles. It is the most common primary orbital tumour among children, usually occurring below the age of 15 years (90%). Clinical features: It classically presents as rapidly progressive proptosis of sudden onset in a child of 7-8 years. Massive proptosis due to rhabdomyosarcoma located in the superonasal quadrant (mimmicking acute inflammatory process). The clinical presentation mimics an inflammatory process. The tumour commonly involves the superionasal quadrant; but may invade any pa of the orbit. Ref:- A K KHURANA; pg num:-394', 'role': 'assistant'}]