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
High dose methotrexate is used for the treatment of(REPEAT) 
Select and explain. 
A. Osteosarcoma, B. Rhabdomyosarcoma, C. Retinoblastoma, D. Ewing's sarcoma
A: Osteosarcoma
Answer: A: Osteosarcoma 
Explanation: Ref: Harrison's 17th/612 Drugs used for osteosarcoma are: Doxorubicin Ifosfamide Cisplatin High dose methotrexate with leucovorin