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 most useful in differentiating an acute periodontal abscess from periapical abscess? \nSelect and explain. \nA. Type of exudates, B. Nature of swelling, C. Intensity of pain, D. Result of periodontal probing', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]