A train is a form of transport consisting of a series of connected vehicles that generally runs along a rail track to transport freight or passengers. ___________ for a train is provided by a separate locomotive which is attached to the train head. 火车是一种交通工具，由一系列连接的车辆组成 ，它通常沿着铁轨运行，运送货物或旅客。列车的_______提供由单独的机车完成，它连接在车头上。
A、motive power 动力
B、driving force 驱动力
C、strength 力量