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': 'The disclosing agent used in modified Quigley Hein plaque index is: \nSelect and explain. \nA. Carbol fuchsin, B. Basic fuchsin, C. Sodium Fluorescein, D. Two tone dye', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]