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': 'Which of the following microorganisms are commonly present in large percentage of root canal treated teeth that present with persistent periradicular lesions indicative of failed treatment? \nSelect and explain. \nA. Porphyromonasgingivalis, B. Tannerella forsythia, C. Dialisterinvisus, D. Enterococcus faecalis', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]