Which one of the following ions has same number of unpaired electrons as that of${\mathrm{V}}^{3+}$ ion?

V³⁺ has 3d² outer electronic configuration with 2 unpaired electrons. 

Ni²⁺  has 3d⁸ outer electronic configuration with 2 unpaired electrons. 

Hence, V³⁺ and  Ni²⁺ have same number of unpaired electrons.