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': 'Plasma cells are mostly seen in one of the stages of gingivitis \nSelect and explain. \nA. Initial lesion, B. Early lesion, C. Established lesion, D. Advanced lesion', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]