This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Chemotherapy, Subject name: Pharmacology
[{'content': 'High dose Methotrexate is used for treatment of \nSelect and explain. \nA. Osteosarcoma, B. Rhabdomyosarcoma, C. Retinoblastoma, D. Ewings sarcoma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Refer Harrison 17th/612 Drugs needs for Osteosarcoma Doxorubicin Ifosfamide Cisplatin High dose Methotrexate with Leucovorin', 'role': 'assistant'}]