—Could you please tell me             ?

—Bus No. 536 will take you right there.

A. where Hubei Museum is

B. what Hubei Museum is like

C. which bus I should take to Hubei Museum

如图所示，固定的水平长直导线中通有电流I，矩形线框与导线在同一竖直平面内，且一边与导线平行．线框由静止释放，在下落过程中(　　)

A．穿过线框的磁通量保持不变

B．线框中感应电流方向保持不变

C．线框所受安培力的合力为零

D．线框的机械能不断减小