火车以1m／s²的加速度在水平轨道上匀加速行驶，一乘客把手伸到窗外从距地面2.5m高处自由释放一物体，不计空气阻力，物体落地时与乘客的水平距离为[    ]

A．0m

B．0.25m

C．0.5m

D．1m

After using a C0₂ portable extinguisher，it should be（）.

A.put back in service if some C0₂ remains

B.hydrostatically tested

C.retagged

D.recharged