frankly speaking on the first instance, E was my last choice bcos of the usage of been. but i think only this sentence makes the most of meaning. A and B give an impression dat king & queen bombed out he civilians. C is awkward. it gives meaning that civilians bombed out whn K & Q visited factories. dat leaves D & E. E is the best choice bcos it means civilians had been bombed out b4 K & Q visited them
During the war, the king and queen constantly visited factories and bombed out civilians.
bombed out civilians
they bombed the civilians out
civilians bombed out
civilians who had bombed out
civilians who had been bombed out