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': 'Horrok&;s apparatus determines Chloride which has to have a holding level of - \nSelect and explain. \nA. 0.1 mg\\/L, B. 1 mg\\/L, C. 0.01 mg\\/L, D. 0.5 mg\\/L', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Roughly 2.5 grams of good quality bleaching powder would be required to disinfect 1,000 liters of water.This will give an approximate dose of 0.7 mg of applied chlorine per litre of water (refer pgno:718 park 23rd edition)', 'role': 'assistant'}]