Answer: B. Dictatorships use lies to manipulate the populace.
Option B is the one that best expresses the theme of the passage. In this passage, the animals feel horrified when they discover that the horse is about to be sent to the slaughterer. The animals can see with their own eyes that he is being taken by the slaughterer's van. However, the pigs tell the animals that this is simply a confusion and that Boxer was being sent to the vet. This is a clear lie, but it demonstrates how dictatorships often use lies in order to manipulate the populace.