This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Environment and Health, Subject name: Social & Preventive Medicine
[{'content': 'Concentration of bleaching powder used for disinfection oi urine and faeces is \nSelect and explain. \nA. 5%, B. 10%, C. 15%, D. 20%', 'role': 'user'}, {'content': 'Answer: A \nExplanation: 108) Ans: a (5%) Ref: Park 20th ed pi 18Concentration of bleaching powder used for disinfection of faeces anc urine is 5%.Agents suitable for disinfection of faeces and urineDisinfectantAmount per literConcentrationBleaching powder50 g5%Crude phenol100 ml10%Cresol50 ml5%Fonnalin100ml10%', 'role': 'assistant'}]