Solve this :

Q. Two small balls A and B, each of mass m, are joined rigidly at the ends of a light rod of length L. They are placed on a frictionless horizontal surface. Another ball of mass 2 m moving with speed u towards one of the ball and perpendicular to the length of the rod on the horizontal frictionless surface as shown in the figure. If the coefficient of restitution is 1/2 then the angular speed of the rod after the collision will be :

$$\begin{gathered} \left(\mathrm{a}\right) \frac{4}{3}\frac{\mathrm{u}}{\mathrm{L}} \left(\mathrm{b}\right) \frac{\mathrm{u}}{\mathrm{L}} \\ \left(\mathrm{c}\right) \frac{2}{3}\frac{\mathrm{u}}{\mathrm{L}} \left(\mathrm{d}\right) \mathrm{None} \mathrm{of} \mathrm{these} \end{gathered}$$