A body $\mathrm{m}$, rests on the smooth floor while another body $\mathrm{m}_{2}$ is placed on top. All surfaces are smooth. If a velocity $\mathrm{v}_{0}$ is given to $\mathrm{m}_{1}$ towards the right, and the collision of $\mathrm{m}_{2}$ with the side of $\mathrm{m}_{1}$ is elastic the time taken for $\mathrm{m}_{2}$ to slide off is $\left(\frac{\mathrm{m}_{2}}{\mathrm{~m}_{1}}=\mathrm{k}\right)$
(a) $\left(\frac{2 \mathrm{k}+3}{\mathrm{k}+1}\right)\left(\frac{\mathrm{d}}{\mathrm{v}_{0}}\right)$
(b) $\frac{2 \mathrm{~d}}{\mathrm{v}_{0}}, \frac{1}{\mathrm{k}+1}$
(c) $\frac{3 \mathrm{~d}}{\mathrm{v}_{0}}$
(d) $\frac{1-k}{1+k} \cdot \frac{d}{v_{0}}$