An $HCl$ molecule has rotational,translational,and vibrational motions. If the $rms$ velocity of $HCl$ molecules in its gaseous phase is $\bar{v}$,$m$ is its mass,and $k_B$ is the Boltzmann constant,then its temperature will be:

• A
  $\frac{m\bar{v}^2}{3k_B}$
• B
  $\frac{m\bar{v}^2}{7k_B}$
• C
  $\frac{m\bar{v}^2}{5k_B}$
• D
  $\frac{m\bar{v}^2}{6k_B}$