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
[{'content': 'Which of the following tumor is least sensitive to radiation? \nSelect and explain. \nA. Bronchogenic carcinoma, B. Adenocarcinoma of colon, C. Malignant melanoma, D. Osteogenic sarcoma', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. Malignant melanoma', 'role': 'assistant'}]