This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Radiotherapy, Subject name: Radiology
Radioresistant tumor is - 
Select and explain. 
A. Ewings sarcoma, B. Retinoblastoma, C. Osteosarcoma, D. Neuroblastoma
C: Osteosarcoma
Answer: C: Osteosarcoma 
Explanation: Ans. is 'c' i.e., Osteosarcoma o Most radio-resistant tumors areOsteosarcomaMelanomaHepatic carcinomaPancreatic carcinoma