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: Pathology
Tender submandibular swelling is mostly due to: 
Select and explain. 
A. Ludwig's angina, B. Stone or Sialolithiasis, C. Enlarged lymph nodes, D. All of the above
C: Enlarged lymph nodes
Answer: C: Enlarged lymph nodes 
Explanation: None