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: Radiology
Which of the following is not sensitive to radiotherapy? 
Select and explain. 
A. Ewings sarcoma, B. Osteosarcoma, C. Wilms', D. Neuroblastoma
B: Osteosarcoma
Answer: B: Osteosarcoma 
Explanation: Ans. Osteosarcoma