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: Pharmacology
Methotrexate is used in high doses in - 
Select and explain. 
A. Osteosarcoma, B. Retinoblastoma, C. Rhabdomyosarcoma, D. Ewig's sarcoma
A: Osteosarcoma
Answer: A: Osteosarcoma 
Explanation: Ans. is 'a' i.e., Osteosarcoma o High dose methotrexate with leucoverin is indicated for chemotherapy in osteosarcoma.