A body of mass $m_1$ moving with an unknown velocity of $v_1 \hat{\mathrm{i}},$ undergoes a collinear collision with a body of mass $m_2$ moving with a velocity $v_2 \hat{\mathrm{i}}.$ After the collision, $m_1$ and $m_2$ move with velocities of $v_3\mathrm{ }\hat{\mathrm{i}}$ and $v_4\mathrm{ }\hat{\mathrm{i}},$ respectively. If $m_2=0.5\mathrm{ }{m}_1$ and $v_3=0.5 v_1,$ then $v_1$ is:

• A

  $v_4-\frac{v_2}{4}$
• B

  $v_4-\frac{v_2}{2}$
• C

  $v_4+v_2$
• Correct answer
  D

  $v_4-v_2$

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