A 3 kg sphere makes an inelastic collision with another sphere at rest and they stick together after collision. After collision, the composite mass moves with a speed of $\bigg( \large\frac{1}{4} \bigg)^{th}$ of the initial velocity of 3 kg sphere. The mass of second sphere is

Question

$\begin {array} {1 1} (1)\;12\: kg & \quad (2)\;9\: kg \\ (3)\;6\: kg & \quad (4)\;3\: kg \end {array}$