Which of These Gases (He, N₂O, N₂) Has the Same $\circ$

Which of these gases (He, N₂O, N₂) has the same root-mean-square speed at 25 ^$\circ$ C as CO₂?

A) He
B) N₂O
C) N₂
D) They are all the same as CO₂.
E) They are all different from CO₂.