A gas can be liquified when its temperature is below the critical temperature, by cooling or compressing it.Gases which have high critical temperatures (such as \\\\({Cl}_{2}, N{H}_{3}, C{O}_{2}, S{O}_{2}\\\\) etc.,) can be liquified by applying a suitable pressure alone. Permanent gases (such as \\\\({H}_{2}, {N}_{2}, {O}_{2}\\\\) etc.,) cannot be liquified by the action of pressure and cooling.Hence, option A is correct.