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': 'In two years after RCT, a patient complains of "Pain over the gum" of that tooth and the tooth is tender to percussion, then the treatment of choice is: \nSelect and explain. \nA. Extraction, B. Retreatment of the root canal, C. Apicoectomy and a retro fill, D. An antibiotic course and Re-evaluation at next visit', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]