The arrangement of ${\mathrm{x}}^{-}$ ions around${\mathrm{A}}^{+}$ ion m solid AX is given in the figure (not drawn to scale). If the radius of ${\mathrm{x}}^{-}$ is 250 pm, the radius of ${\mathrm{A}}^{+}$is:

The following formula relates the sphere's radius to the limiting radius in an octahedral void:

${\mathrm{r}}_{\text{void }}=0.414{\mathrm{r}}_{\text{sphere }}$

${\mathrm{r}}_{{\mathrm{A}}^{+}}=0.414{\mathrm{r}}_{{\mathrm{X}}^{-}}=0.414\times 250=103.5\approx 104\mathrm{pm}$

Correct option is A.