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: Pathology
Tumour that doesn't show spontaneous regression: 
Select and explain. 
A. Neuroblastoma, B. Retinoblastoma, C. Malignant melanoma, D. Osteosarcoma
D: Osteosarcoma
Answer: D: Osteosarcoma 
Explanation: None