Read the passage from Animal Farm . "Boxer!" cried Clover in a terrible voice. "Boxer! Get out! Get out quickly! They're taking you to your death!" All the animals took up the cry of "Get out, Boxer, get out!" But the van was already gathering speed and drawing away from them. It was uncertain whether Boxer had understood what Clover had said. But a moment later his face disappeared from the window and there was the sound of a tremendous drumming of hoofs inside the van. He was trying to kick his way out. The time had been when a few kicks from Boxer's hoofs would have smashed the van to matchwood. But alas! his strength had left him; and in a few moments the sound of drumming hoofs grew fainter and died away. In desperation the animals began appealing to the two horses which drew the van to stop. "Comrades, comrades!" they shouted. "Don't take your own brother to his death!" But the stupid brutes, too ignorant to realise what was happening, merely set back their ears and quickened their pace. Boxer's face did not reappear at the window. Too late, someone thought of racing ahead and shutting the five-barred gate; but in another moment the van was through it and rapidly disappearing down the road. Boxer was never seen again. Which statement best expresses the theme of the passage?