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': 'PMA index is used to record the status of: \nSelect and explain. \nA. Gingival disease, B. Carious teeth, C. Root caries, D. Periodontal disease', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]