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
Temporary and permanent removed by – 
Select and explain. 
A. Boiling, B. Addition of lime, C. Permutit method, D. All
C: Permutit method
Answer: C: Permutit method 
Explanation: Permutit method (Base exchange process) can remove both permanent and temporary hardness.