A sphere of mass m moving horizontally $V_0$ collides against a pendulum bob of mass m. If the two masses stick together after the collision then the maximum height attained is

Question

 

 

$$\begin {array} {1 1} (a)\;\frac{V_0^2}{2g} & \quad (b)\;\frac{V_0^2}{4g} \\ (c)\;\frac{V_0^2}{6g} & \quad  (d)\;\frac{V_0^2}{8g} \end {array}$$