Outer mot electronic Configuration	Oxidation States
A) $[{\text{Ar] 3d}}^2{\text{4s}}^2$	1)  + II, +III, +IV, +V, +VI
B) $[{\text{Ar] 3d}}^5{\text{4s}}^1$	2) + II, +III, +IV, +V, +VI , +VII
C) $[{\text{Ar] 3d}}^5{\text{4s}}^2$	3) +II
D) $[{\text{Ar] 3d}}^{10}{\text{4s}}^2$	4) + II, +III, +IV

d-block elements exhibit variable oxidation state. The outer most electrons configuration of d-block elements is ${\text{ns}}^{\text{1-2}}{\text{(n-1)d}}^{\text{1-10}}$. They show common oxidation state of +2 due to loss of ${\text{ns}}^{\text{2}}$electrons.