$K^{+},Ar,C{a}^{2+}$ and $S^{2-}$ contains:

The correct option is A same electronic configuration and atomic volume
Electronic configuration of: ,

$K^{+}$ is $2,8,8$

$Ar$ is $2,8,8$

$C{a}^{+2}$ is $2,8,8$

$S^{2-}$ is $2,8,8$

Hence electronic configuration of all the four species is equal

Hence the the structure of the species remains the same which leads to the equal atomic volume.