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: Dental
[{'content': 'Obturation may be done in the initial visit if \nSelect and explain. \nA. There is necrotic pulp, B. There is a swelling, C. The tooth is vital, D. The tooth is nonvital', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]