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

(i) MnO₄^-
Since Mn has no d (d⁰) electrons, it is in the +7 oxidation state. Therefore, neither a d-d transition nor paramagnetism exist. The charge transfer spectra are what give it its colour.

(ii)  CrO₄^2-

 Cr has no d (d⁰) electrons since it is in the +6 oxidation state. Therefore, neither a d-d transition nor paramagnetism exist.

(iii) MnO₄^2-
​The d-d transition and paramagnetism are caused by Mn being in the +6 oxidation state, which implies it has one d (d¹) electron.

(iv)Cr₂O₂^7-  

It has no d (d⁰ ) electrons and is in the +6 oxidation state. There is thus no d-d. 

Hence, the correct option is option (D) MnO₄^-