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': 'The freshly prepared ORS (Oral Rehydration Solution) should not be used after \nSelect and explain. \nA. 6 hours, B. 24 hours, C. 18 hours, D. 12 hours', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Reduced Osmolarity Oral Rehydration Solution (Low Na ORS): WHO NEW ORS\nComposition (grams)\n\nSodium chloride - 2.6\nPotassium chloride - 1.5\nSodium citrate - 2.9\nGlucose - 13.5\nTotal -\xa0 20.5\n\nOsmolar concentration (mmol/litre)\n\nSodium\xa0- 75\nPotassium - 20\nChloride - 65\nCitrate - 10\nGlucose - 75\nTotal -245', 'role': 'assistant'}]