A spherical solid ball of volume $V$ is made of a material of density $\rho_{1}$. It is falling through a liquid of density $\rho_{2}\left(\rho_{2}<\rho_{1}\right.$ ) [Assuming that the liquid applies a viscous force on the ball that is proportional to the square of its speed $v$, i.e., $\left.F_{\text {viscous }}=-k v^{2}(k>0)\right]$. The terminal speed of the ball is [2008]
(A) $\sqrt{\frac{V g\left(\rho_{1}-\rho_{2}\right)}{k}}$
(B) $\frac{V g \rho_{1}}{k}$
(C) $\sqrt{\frac{V g \rho_{1}}{k}}$
(D) $\frac{V g\left(\rho_{1}-\rho_{2}\right)}{k}$