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': 'Both temporary and permanent hardness of water can be removed by: \nSelect and explain. \nA. Boiling, B. Adding lime, C. Adding sodium carbonate, D. None of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Temporary hardness can be removed by: Boiling Adding lime Adding sodium carbonate Permutit process Permanent hardness can be removed by Adding sodium carbonate Base exchange resins Ref: Park 21st edition page: 672.', 'role': 'assistant'}]