Billy: I’ve been fixing the computer for over three hours, but it still doesn’t work.

Nana: Why don’t you take a rest and try 　　　?  Maybe you’ll do better then.

A．early

B．finally

C．later

D．once

如图所示，通电直导线长为0.5m，通以1A的电流，置于匀强磁场中，磁感应强度为0.1T，导线与磁场方向垂直．则导线受到安培力的大小和方向（　　）

A．0.05N，水平向左

B．0.2N，水平向左

C．0.05N，水平向右

D．0.2N，水平向右