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': 'Citric acid concentration in MTAD is: \nSelect and explain. \nA. 4.25%, B. 3.75%, C. 1%, D. 0.50%', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Composition\n\nTetracycline:\n\n– It is bacteriostatic, broad spectrum antibiotic.\n– It has low pH and acts as calcium chelator.\n– It removes smear layer.\n– It has property of substantivity.\xa0\n– It promotes healing.\n\nCitric acid (4.25%): It is bactericidal in nature and removes smear\xa0layer.\nDetergent (Tween 80): It decreases surface tension.', 'role': 'assistant'}]