All the preparations for the work_______, we’re ready to start.

A．are completed

B．have been completed

C．completed

D．had been completed

卫某在偏僻的乡间小路上运输毒品，蔡某见状上前抢劫，卫某为了保护毒品以暴力进行反抗，致蔡某重伤。卫某的行为属于( )。

A．正当防卫

B．防卫过当

C．紧急避险

D．故意伤害