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': 'Initial threshold of the electric test in a traumatic tooth is to: \nSelect and explain. \nA. Establish base line of the physical status of the pulp, B. Is positive in healthy pulp, C. Is negative in root canal tooth, D. Is repeated after 30 days', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]