The number of d-electrons in $F{e}^{2+}$(Z=26) is not equal to the number of electrons in which one of the following ?

Electronic configuration of $F{e}^{2+}$ is [Ar] $3d^{6}4s^0$.
$\therefore$ Number of electrons = 6
Mg - $1s^{2}2s^{2}2p^{6}3s^2$ (6s electrons)
It matches with the 6d electrons of $F{e}^{2+}$
$Cl-1s^{2}2s^{2}2p^{6}3s^{2}3p^5$ (11 p electrons)
It does not match with the 6d electrons of $F{e}^{2+}$
Fe - [Ar] $3d^{6}4s^2$ (6d electrons)
It does not match with the 6d electrons of $F{e}^{2+}$
Ne - $1s^{2}2s^{2}2p^6$ (6 p electrons)
It matches with the 6d electrons of $F{e}^{2+}$ .
Hence, Cl had 11p electrons which does not matches in number with 6d electrons of $F{e}^{2+}$.