A ball is dropped from a height of \(5~\text {m}.\) If it rebounds up to a height of \(1.8~\text {m},\) then the ratio of velocities of the ball after and before the rebound will be:
1. \(\dfrac{3}{5}\)

2. \(\dfrac{2}{5}\)

3. \(\dfrac{1}{5}\)

4. \(\dfrac{4}{5}\)