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': 'All of the following modalites can be used for in situ ablation of liver secondaries, except: \nSelect and explain. \nA. Ultrasonic waves, B. Cryotherapy, C. Alcohol, D. Radiofrequency', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. Alcohol', 'role': 'assistant'}]