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
Constant feature associated with a radicular cyst 
Select and explain. 
A. An impacted tooth, B. A missing tooth, C. A non-vital tooth, D. An anomalous tooth
C: A non-vital tooth
Answer: C: A non-vital tooth 
Explanation: None