Face the heat

The minimum radius of drop of water that might evaporate at 0 degree Centigrade without heat being supplied to it is $x\times 10^{-11}\text{ m}$ , find $x$ .

Take surface tension as $120\times 10 ^{-3} \text{ N/m}$ and $L_{v}=660 \text{ KCal/kg}, J=4 \text{ J/cal}$ .