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': 'Most important criteria in using irrigating solution is \nSelect and explain. \nA. Volume of irrigation, B. Thickness of syringe used, C. Concentration of irrigant, D. None of above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]