Read the passage from Animal Farm.

It had come to his knowledge, he said, that a foolish and wicked rumour had been circulated at the time of Boxer's removal. Some of the animals had noticed that the van which took Boxer away was marked "Horse Slaughterer," and had actually jumped to the conclusion that Boxer was being sent to the knacker's. It was almost unbelievable, said Squealer, that any animal could be so stupid. Surely, he cried indignantly, whisking his tail and skipping from side to side, surely they knew their beloved Leader, Comrade Napoleon, better than that? But the explanation was really very simple. The van had previously been the property of the knacker, and had been bought by the veterinary surgeon, who had not yet painted the old name out. That was how the mistake had arisen.

Which statement best expresses the theme of the passage?

Workers need to organize for better health care.
Dictatorships use lies to manipulate the populace.
Sometimes, you cannot trust what you see with your own eyes.
Relying on others is the only way to get through difficult times.