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: ENT
Thornwaldt's cyst is 
Select and explain. 
A. Laryngeal cyst, B. Nasopharyngeal cyst, C. Ear cyst, D. None
B: Nasopharyngeal cyst
Answer: B: Nasopharyngeal cyst 
Explanation: None