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
[{'content': 'Constant feature associated with a radicular cyst \nSelect and explain. \nA. An impacted tooth, B. A missing tooth, C. A non-vital tooth, D. An anomalous tooth', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]