For the structure with fundamental and accessory parts, which statements is correct?

A、The load acting on the accessory part has no effect on the internal force and displacement of the fundamental part;;

B、The load acting on the accessory part has effect on the internal force and displacement of the fundamental part, but the load acting on the fundamental part has no effect on the internal force and displacement of the accessory part;;

C、The load acting on the accessory part has impact on the internal force and displacement of the fundamental part. The load acting on the fundamental part has no impact on the internal force of the accessory part, but may have impact on the displacement of the accessory part.;

D、All of the above is wrong.