(iv) Zirconium is best refined by zonc refining method.

Explanation

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks whether zirconium is best refined by the zone refining method. We need to evaluate the validity of this statement.

2. **Defining Zone Refining Method**: Zone refining is a technique used for purifying metals and semiconductors. It involves melting a small region (zone) of a solid material and moving this molten zone along the material. The key principle is that impurities are more soluble in the molten state than in the solid state.

3. **Principle of Zone Refining**: In zone refining, as the molten zone moves, impurities tend to concentrate in the molten part. When the molten zone moves away, the solid part remains purer as the impurities are left behind in the molten zone.

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