Two blocks of masses $m_1=2 kg$ and $m_2=4kg$ are moving in the same direction with speeds $V_1=6 m/s$ and $V_2=3 m/s$, respectively on a frictional less surface. An ideal spring with spring constant $k= 30000\;n/m$ is attached to the bakside of $m_2.$ Then the maxiimum compression of the spring after collision will be

Question

$\begin{array}{1 1} (a)\;0.06\;m & \quad (b)\;0.04\;m \\ (c)\;0.02\;m & \quad  (d)\;none\;of\;these \end{array}$