Read the excerpt below and answer the question. There was, as Squealer was never tired of explaining, endless work in the supervision and organisation of the farm. Much of this work was of a kind that the other animals were too ignorant to understand. For example, Squealer told them that the pigs had to expend enormous labours every day upon mysterious things called "files," "reports," "minutes," and "memoranda." These were large sheets of paper which had to be closely covered with writing, and as soon as they were so covered, they were burnt in the furnace. This was of the highest importance for the welfare of the farm, Squealer said.

Which of Animal Farm's themes is illustrated in this excerpt?

working-class loyalty
social-class hierarchy
corruption of power
manipulation of language