Which one of the following complexes will most likely absorb visible light?

(At nos. Sc= 21, Ti= 22, V = 23, Zn= 30)

The electronic configurations of metallic ions in the complexes are

${ }_{21}5{\mathrm{c}}^{3+}\left(3{\mathrm{d}}^0\right){;}_{22}{\mathrm{Ti}}^{4+}\left(3{\mathrm{d}}^0\right){;}_{23}\mathrm{V}\left(3{\mathrm{d}}^2\right){;}_{30}{\mathrm{Zn}}^{2+}\left(3{\mathrm{d}}^{10}\right)$

Only vanadium complex has two unpaired electrons and thus can undergo d-d transition requiring the absorption of visible light.