A body of mass $\mathrm{m}_{2}$ has one of its surfaces in the form of a quarter circle of radius $\mathrm{R}$. A mass $\mathrm{m}_{1}$ is placed on top of a plunger assembly. Assume all surfaces are frictionless. The final velocity of $m_{2}$, if plunger starts to descend from initial position $B$ as shown, is
(a) $\sqrt{2 \mathrm{gR} \cdot \frac{\mathrm{m}_{1}}{\mathrm{~m}_{2}}}$
(b) $\sqrt{2 \mathrm{gR}(1-\sin \theta) \frac{\mathrm{m}_{1}}{\mathrm{~m}_{2}}}$
(c) $\sqrt{2 g R(1-\cos \theta) \frac{m_{1}}{m_{2}}}$
(d) $\sqrt{2 g R \cdot \frac{m_{2}}{m_{1}}}$