Which of the following gases must be cooled below room temperature before it will cool further on Joule-Thomson expansion?

Helium has an inversion temperature of about $40\mathrm{K}$, far below room temperature, so at $298\mathrm{K}$ it warms on throttling. $\mathrm{N}{}_2$ ($621\mathrm{K}$), $\mathrm{O}{}_2$ ($764\mathrm{K}$) and $\mathrm{CO}{}_2$ ($1500\mathrm{K}$) all have $T_i$ above room temperature.