A boy is seated on top of a hemispherical mount of ice of radius R. He is given a little push and he starts sliding down the ice. If ice is frictionless, the boy will leave the ice at a point whose height is
1
\(\frac{3 R}{4}\)
2
\(\frac{2 R}{\sqrt{3}}\)
3
\(\frac{2 R}{3}\)
4
\(\frac{R}{3}\)