If the ionic radii of${\mathrm{K}}^{+}$ and ${\mathrm{F}}^{-}$ are about $1.34\text{Å}$ each, then the expected value of atomic radii of $\mathrm{K}$ and $\mathrm{F}$ should be respectively :

If the ionic radii of ${\mathrm{K}}^{+}$ and ${\mathrm{F}}^{-}$ are about $1.34 \mathrm{A}˚$ each, then the expected values of atomic radii of $\mathrm{K}$ and $\mathrm{F}$should are $2.31$ and $0.64\text{Å}$respectively.

 Cations are always shorter than their parent atom, anions are always larger.

Thus radii of ${\mathrm{K}}^{+}$will be more than $1.34$and that of ${\mathrm{F}}^{-}$ will be less than$1.34$.

Hence, option A is correct.