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': 'Apexification is the treatment of choice for a permanent\ntooth with wide open apex when \nSelect and explain. \nA. The pulp is necrotic, B. The pulp is vital, C. The pulp and root canals are calcified, D. There is a traumatic pulp exposure during cavity preparation', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]