`{:(,"Column A",,,"Column B"),(A.,"Sedimentation","( )",a.,"Softened water"),(B.,"Filtration","( )",b.,"Additional of alum"),(C.,"Chlorination","( )",c.,"Removal of suspended impurities"),(D.,"Permutit","( )",d.,"Purification of drinking water"):}`

Explanation

To solve the matching question between Column A and Column B, we need to understand the processes described in Column A and their corresponding effects or purposes listed in Column B.

### Step-by-Step Solution:

1. **Understand Sedimentation**:
- Sedimentation is a process where heavier particles in water settle down due to gravity. To speed up this process, alum (a chemical compound) is added. This helps impurities to settle faster.
- **Match**: Sedimentation (A) → Addition of alum (B).

2. **Understand Filtration**:
- Filtration is the process of removing suspended impurities from water. This is done by passing water through a filter, which allows clean water to pass while trapping impurities.
- **Match**: Filtration (B) → Removal of suspended impurities (C).

3. **Understand Chlorination**:
- Chlorination involves adding chlorine to water to disinfect it. This process kills harmful bacteria and pathogens, making the water safe for drinking.
- **Match**: Chlorination (C) → Purification of drinking water (D).

4. **Understand Permutit**:
- Permutit is a method used to convert hard water into soft water. Hard water contains high levels of calcium and magnesium, and permutit helps to remove these ions.
- **Match**: Permutit (D) → Softened water (A).

### Final Matches:
- A (Sedimentation) → B (Addition of alum)
- B (Filtration) → C (Removal of suspended impurities)
- C (Chlorination) → D (Purification of drinking water)
- D (Permutit) → A (Softened water)

### Summary of Matches:
- A → B
- B → C
- C → D
- D → A