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
A patient with oral cancer, had ipsilateral lymph node measuring 2 cm, single in number with capsular spread. According to TNM staging it is included under: 
Select and explain. 
A. Nx, B. N1, C. N2, D. N3
D: N3
Answer: D: N3 
Explanation: Nx: Nodal status can't be assessed.
No: No lymph nodes.
N1: Single ipsilateral lymph node <3 cm
N2:
A: Single ipsilater lymph 3.6 cm
B: Multiple ipsilater lymph <6 cm
C: Bilateral or contralateral lymph nodes <6 cm.
N3:
Any lymph node with >6 cm, or
Any lymph node with capsular invasion.