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': 'Chlorhexidine as a root canal irrigant is \nSelect and explain. \nA. Active against gram +ve , gram –ve bacterias and to some extent Virus with lipid envelop., B. Normally used at 2% conc, C. A poly biguinide, D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]