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
Secondaries in the neck with no obvious primary malignancy is most often due to - 
Select and explain. 
A. Ca. Stomach, B. Ca. Larynx, C. Ca. Nasopharynx, D. Ca. Thyroid
C: Ca. Nasopharynx
Answer: C: Ca. Nasopharynx 
Explanation: None