$\mathrm{Li}^{\dagger}<\mathrm{Na}^{+}<\mathrm{Cs}^{+}$
and the order of the size of given anions is
$\mathrm{I^-}>\mathrm{F^-}$
Thus, when the cation is largest and anion is smallest the cation to anion size ratio is maximum. Hence cation to anion size ratio is maximum
$(i)$ $Li < B < Be < C$ $(ii)$ $O < N < F$ $(iii)$ $Be < N < Ne$