At the age when many people ______ their first job, the youngsters of The Sunday Times Rich List are buying country estates or jetting off to their homes overseas.

A．were looking for

B．have looked for

C．are looking for

D．looked for

小球从空中A点竖直上抛，下落过程落到距A点正下方h处C点的速度恰好是下落到距A点正上方h处B点的速度的2倍，则小球上升过程所能达到的最高点O距A点的高度是（　　）

A．

B．

C．h

D．2h