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': 'Tooth whitening strip is: \nSelect and explain. \nA. H2O2, B. HF, C. Carbamide peroxide, D. Sodium perborate', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Hydrogen peroxide used in dentistry as a whitening agent ranges in concentration between 5 and 35%.\nRef :Grossman’s endodontics,13th edition, pg no:504', 'role': 'assistant'}]