`25ml` of a `0.1(M)` solution of a stable cation of transition metal `z` reacts exactly with `25 ml` of `0.04(M)` acidified `KMnO_(4)` solution. Which of the following is most likely to represent the change in oxidation state of `Z` correctly?
A. `Z^(+) rarr Z^(2+)`
B. `Z^(2+) rarr Z^(3+)`
C. `Z^(3+) rarr Z^(4+)`
D. `Z^(2+) rarr Z^(4+)`
