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': 'Secondaries in the neck with no obvious primary malignancy is most often due to: \nSelect and explain. \nA. CA Stomach, B. CA Larynx, C. CA Nasopharynx, D. CA Thyroid', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]