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': 'Cannon balls seen in the lungs are characteristic of: \nSelect and explain. \nA. Seminoma testes, B. Carcinoid, C. Hypernephroma, D. Pheochromocytoma', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Pheochromocytoma', 'role': 'assistant'}]