If the kinetic energy in $J$,of $CH_4$ (molar mass $= 16 \ g \ mol^{-1}$) at $T(K)$ is $X$,the kinetic energy in $J$,of $O_2$ (molar mass $= 32 \ g \ mol^{-1}$) at the same temperature is

• A
  $X$
• B
  $2 X$
• C
  $X^2$
• D
  $\frac{X}{2}$