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 ailment most commonly causes periodontal disorder: \nSelect and explain. \nA. Hypophosphatemia, B. Wegener's granulomatosis, C. Multiple myeloma, D. AIDS", 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]