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': 'In orthodontics activity index means: \nSelect and explain. \nA. RANK/ and OPG in GCF, B. IL-1 beta/IL R-A in GCF, C. IL-1/IL6 in saliva, D. IL-6/11.8 in saliva', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]