GKFix MCQ Question

How does the ion exchange method remove hardness from water?

• A. By filtering out Ca²⁺ and Mg²⁺ ions
• B. By precipitating Ca²⁺ and Mg²⁺ ions
• C. By boiling the water
• D. By exchanging Ca²⁺ and Mg²⁺ ions with Na⁺ ions