At the same temperature,the root mean square velocities of two gases are $v_1$ and $v_2$,and their molar masses are $m_1$ and $m_2$ respectively. Which of the following relations is correct?

• A
  $\frac{m_1}{v_1^2} = \frac{m_2}{v_2^2}$
• B
  $m_1v_1 = m_2v_2$
• C
  $\frac{m_1}{v_1} = \frac{m_2}{v_2}$
• D
  $m_1v_1^2 = m_2v_2^2$