Let us match the characteristics with the respective elements: (a) Scandium (Sc) exhibits only a +3 oxidation state because losing its three valence electrons gives it a highly stable noble gas configuration . (b) Manganese (Mn) gives the greatest number of oxidation states (from +2 to +7) due to the involvement of maximum unpaired electrons in its $3d$ and $4s$ orbitals . (c) Chromium (Cr) acts as a strong reducing agent in its +2 oxidation state ($Cr^{2+}$) because its oxidation to $Cr^{3+}$ changes its configuration from $d^4$ to a highly stable half-filled $t_{2g}^3$ configuration . (d) Zinc (Zn) is not considered a transition metal because it has a completely filled $d^{10}$ electronic configuration in its ground state as well as in its common oxidation state (+2) . Therefore, the correct match is (a)-(iii), (b)-(i), (c)-(iv), (d)-(ii).