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': "A patient with known mutation in the `RB gene' is `disease free' from Retinoblastoma. The patient is at highest risk of developing which of the following malignancies – \nSelect and explain. \nA. Renal cell carcinoma, B. Osteosarcoma, C. Pinealoblastoma, D. Chondrosarcoma", 'role': 'user'}, {'content': 'Answer: B \nExplanation: Most common secondary tumor in survivors of retinoblastoma is osteosarcoma.', 'role': 'assistant'}]