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': 'Incidence of Gingivitis in pregnency is \nSelect and explain. \nA. 10-20%, B. 20-30%, C. 40-50%, D. 50-100%', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]