Which Set of Gases Is Listed from Highest to Lowest $\degree$

Which set of gases is listed from highest to lowest root-mean-square speed at 25 $\degree$ C?

A) HCN $\gt$ Cl₂ $\gt$ CO₂ $\gt$ HBr
B) CO₂ $\gt$ HCN $\gt$ Cl₂ $\gt$ HBr
C) HBr $\gt$ Cl₂ $\gt$ HCN $\gt$ CO₂
D) HBr $\gt$ Cl₂ $\gt$ CO₂ $\gt$ HCN
E) HCN $\gt$ CO₂ $\gt$ Cl₂ $\gt$ HBr