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
Both temporary and permanent hardness of water can be removed by: 
Select and explain. 
A. Boiling, B. Adding lime, C. Adding sodium carbonate, D. None of the above
C: Adding sodium carbonate
Answer: C: Adding sodium carbonate 
Explanation: 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.