a body dropped freely from a height h on to a horizontal plane, bounces up and down and finally comes to rest. the coefficient of restitution is e. the ratio of velocities at the beginning and after two rebounds is

Question

$\begin{array}{1 1} \text{a. $e^2:1$} \\ \text{b. $1:e^2$} \\ \text{c. $1:e$} \\ \text{d. $e:1$} \end{array}$