The correct option is A H2<N2<CH4<CO2
Liquifaction capacity of a gas depends on the value of van der Waals' constant 'a' which is a measure of intermolecular force of attraction.
Weaker the intermolecular forces, more is the difficulty to liquify it.
Lower the value of 'a', more is the difficulty to liquify it,
Hydrogen and nitrogen have a small value of 'a', hence they are difficult to liquify. On the contrary, since the intermolecular forces of attraction are high in CH4 and CO2, they can be easily liquified. The critical temperature of CO2 is higher than that of CH4 and therefore CO2 can be easily liquified.