选A through
首先鄙视一下B,完全不符合句子的意思.那么就比较其他3个
through,across和over的区别
①、through：穿过
I threw it through the window.
Is it quicker to drive round the town,or straight though the centre?
②、across:from one side to the other
（在平面上）越过,在/到……对/面,横过.
I can’t swim across the river.
我不能游到河对岸.
He went across the hall to the door.
他越过大厅到门口.
③、over:翻越过
across和over两者都表示从一侧向另一侧的运动：
She drove over /across the bridge.
但如果越过的是一个高的物体,则用over:
He climbed over the wall.
如果越过的是一个平面,则宜用across：
He went across the hall to the door.
across和through都表示“穿过”,“通过”的意思,across表示从物体表面“穿过”、“通过”;而through则表示从内部“穿过”、“通过”.