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 stage of gingivitis is also called subclinical gingivitis \nSelect and explain. \nA. Initial stage, B. Advanced stage, C. Early stage, D. Established stage', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]