A body slides down a frictionless track which ends in a circular loop of diameter \(D\). Then the minimum height h of the body in terms of \(D\) so that it may just complete the loop, is
1
\(h = \dfrac {5D}{2}\)
2
\(h = \dfrac {5D}{4}\)
3
\(h = \dfrac {3D}{4}\)
4
\(h = \dfrac {D}{4}\)