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': 'Glucose levels in gingival crevicular fluid (GCF) are: \nSelect and explain. \nA. Equal to glucose level in serum, B. Zero, C. 3-4 times greater than serum levels, D. More than 10 times the serum Levels', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]