Which one of the following ions has electronic configuration `[Ar]3d^6` (Atomic number of `Mn = 25, Fe = 26,C_@ = 27, N i = 28)`

Options

A. `Ni^(3+)`
B. `Mn^(3+)`
C. `Fe^(3+)` and `Co^(3+)`
D. `Co^(3+)`

Answer

D