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: Social & Preventive Medicine
[{'content': 'Chlorine exerts a disinfectant action in all except \nSelect and explain. \nA. Cetrimide, B. Bleaching Powder, C. Halozone tablets, D. Sodium hypochlorite', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]