Calculate the Root-Mean-Square Speed of Methane, CH₄ (G), at 78 $\degree$

Calculate the root-mean-square speed of methane, CH₄ (g) , at 78 $\degree$ C.

A) 23 m/s
B) 350 m/s
C) 550 m/s
D) 667 m/s
E) 740 m/s