The element that usually does not show variable oxidation states is : A. V B. Ti C. Sc D. Cu

The element that usually does not show variable oxidation states is C. Sc (Scandium).

Scandium (Sc) is a transition metal, but unlike some other transition metals like V (Vanadium), Ti (Titanium), and Cu (Copper), it typically exhibits only one oxidation state, which is +3. In contrast, elements like V, Ti, and Cu can exhibit multiple oxidation states in different chemical compounds and reactions. For example:

A. Vanadium (V) can show oxidation states such as +2, +3, +4, and +5.
B. Titanium (Ti) can exhibit oxidation states such as +2, +3, and +4.
D. Copper (Cu) can have oxidation states like +1 and +2.

So, the correct answer is C. Sc (Scandium).