Which transition element does not exhibit variable oxidation state?

Explanation

To determine which transition element does not exhibit variable oxidation states, we can analyze the electronic configuration of the elements in the d-block.

### Step-by-Step Solution:

1. **Understanding Transition Elements**: Transition elements are those found in the d-block of the periodic table. They typically exhibit multiple oxidation states due to the involvement of d-electrons in bonding.

2. **Identifying Scandium**: Scandium (Sc) is the first element in the d-block with an atomic number of 21. Its electronic configuration is [Ar] 3d¹ 4s².

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