An $\mathrm{H}\mathrm{C}\mathrm{l}$ molecule has rotational, translational and vibrational motions. If the rms velocity of $\mathrm{H}\mathrm{C}\mathrm{l}$ molecules in its gaseous phase is $\stackrel{-}{\mathrm{\nu }}$ , m is its mass and ${\mathrm{k}}_{\mathrm{B}}$ is Boltzmann's constant, then its temperature will be:

• A

  $\frac{\mathrm{m}{\stackrel{-}{\mathrm{\nu }}}^{\mathrm{ }2}}{5{\mathrm{k}}_{\mathrm{B}}}$
• B

  $\frac{\mathrm{m}{\stackrel{-}{\mathrm{\nu }}}^{\mathrm{ }2}}{6{\mathrm{k}}_{\mathrm{B}}}$
• Correct answer
  C

  $\frac{\mathrm{m}{\stackrel{-}{\mathrm{\nu }}}^{\mathrm{ }2}}{3{\mathrm{k}}_{\mathrm{B}}}$
• D

  $\frac{\mathrm{m}{\stackrel{-}{\mathrm{\nu }}}^{\mathrm{ }2}}{7{\mathrm{k}}_{\mathrm{B}}}$

Hence, the correct answer is option: 'C'.