Which one of the following ions exhibits d-d transition and paramagnetism as well?

In case of:
(i)MnO₄⁻, Mn is in the +7 oxidation state which means it has zero d (d⁰) electrons. Hence, there is no d-d transition and no paramagnetism. Its color is due to charge transfer spectra.
(ii)CrO₄²⁻, Cr is in the +6 oxidation state which means it has zero d (d⁰) electrons. Hence, there is no d-d transition and no paramagnetism.
(iii)MnO₄²⁻, Mn is in the +6 oxidation state which means there is one d (d¹) electron which gives rise to d-d transition and paramagnetism.
(iv)Cr₂O₇²⁻, Cr is in the +6 oxidation state which means it has zero d (d⁰) electrons. Hence, there is no d-d transition and no paramagnetism. Its color is due to charge transfer spectra.
Hence, option C is the correct answer.