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 is true about Aggressive periodontitis \nSelect and explain. \nA. Slow progression, rapid episodes possible, B. Familial aggregation is typical feature., C. Local factors often commensurate with observed periodontal destruction, D. Often found in older patients but can be found in all age groups.', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Classification and Clinical Characteristics\nFeatures\nThe 1999 international classification workshop defined the entity of aggressive periodontitis to be characterized by three primary features (Table):\nTABLE \xa0\nDiagnostic Criteria to Distinguish Chronic and Aggressive Periodontitis', 'role': 'assistant'}]