Molecular velocities of two gases at the same temperature $(T)$ are $u_{1}$ and $u_{2}$. Their masses are $m_{1}$ and $m_{2}$ respectively. Which of the following expressions is correct at temperature $T$?

• A
  $\frac{m_{1}}{u_{1}^{2}}=\frac{m_{2}}{u_{2}^{2}}$
• B
  $m_{1} u_{1}=m_{2} u_{2}$
• C
  $\frac{m_{1}}{u_{1}}=\frac{m_{2}}{u_{2}}$
• D
  $m_{1} u_{1}^{2}=m_{2} u_{2}^{2}$