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': 'Calcified mass seen in eyes of children: \nSelect and explain. \nA. Rhabdomyosarcoma, B. Retinoblastoma, C. Metastasis, D. Leukaemia', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans: b (Retinoblastoma)Calcified mass seen in childrenRetinoblastoma is the most common primary intra ocular malignancy in children. The characteristic feature is calcification which can be detected by an USG B scan or CT scan.', 'role': 'assistant'}]