The statement that best describes how propaganda reinforces one of the themes of Animal Farm in this passage is:
It demonstrates that corruption is at the center of totalitarian governments.
In this passage, the pig is using propaganda to justify the change in sleeping arrangements by manipulating language and reasoning to present a seemingly harmless reinterpretation of the rules that were established during the revolution. This reflects how those in power (the pigs) corrupt the original ideals of the revolution for their own comfort and benefit, highlighting the theme of corruption within totalitarian regimes.