The correct statement(s) about $C{r}^{2+}$  and $M{n}^{3+}$ is(are) [Atomic number of $Cr=24$ and $Mn=25$ ]

(A) $C{r}^{2+}$ is a reducing agent: Correct Statement

$C{r}^{2+}$ is a reducing agent as its configuration changes from $d^{4}to{d}^3$ and $C{r}^{3+}$ having a half filled $t_{2g}$ level in presence of $H_{2}O$

(B) $M{n}^{3+}$ is an oxidizing agent: Correct Statement

The change from $M{n}^{3+}toM{n}^{2+}$  results in the half filled $\left(d^5\right)$ configuration which has extra stability.

$\begin{array}{l}M{n}^{3+}\stackrel{+e^{-}}{\to }M{n}^{2+}\\ 3d^{4}4s^{0}3d^{5}4s^0\end{array}$

[Extra stable half filled $\left(d^5\right)$ configuration]

(C) Both $C{r}^{2+}$ and $M{n}^{3+}$ exhibit $d^4$  electronic configuration: Correct Statement

$C{r}^{2+}\stackrel{ }{\to }3d^{4}4s^0$

$M{n}^{3+}\stackrel{ }{\to }3d^{4}4s^0$

(D) When $C{r}^{2+}$ is used as reducing agent chromium ion attain $d^5$ electronic configuration: Incorrect Statement

$\begin{array}{l}C{r}^{2+}\stackrel{ }{\to }C{r}^{3+}+e^{-}\\ 3d^{4}4s^{0}3d^{3}4s^0\end{array}$

Reducing agent: It attains $d^3$ electronic configuration.