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: Surgery
[{'content': 'A testicular tumor in a man aged 60 years is; most likely to be - \nSelect and explain. \nA. Germ cell tumor, B. Sertoli cell tumor, C. Teratocarcinoma, D. Lymphoma', 'role': 'user'}, {'content': 'Answer: D \nExplanation: "Lymphoma is the most common testicular tumor in a patient over the age of 50 and is the most common secondary neoplasm of the testis" - Smith\'s Urology', 'role': 'assistant'}]