Read the passage from Animal Farm.

The animals huddled about Clover, not speaking. The knoll where they were lying gave them a wide prospect across the countryside. Most of Animal Farm was within their view—the long pasture stretching down to the main road, the hayfield, the spinney, the drinking pool, the ploughed fields where the young wheat was thick and green, and the red roofs of the farm buildings with the smoke curling from the chimneys. It was a clear spring evening. The grass and the bursting hedges were gilded by the level rays of the sun. Never had the farm—and with a kind of surprise they remembered that it was their own farm, every inch of it their own property—appeared to the animals so desirable a place. As Clover looked down the hillside her eyes filled with tears. If she could have spoken her thoughts, it would have been to say that this was not what they had aimed at when they had set themselves years ago to work for the overthrow of the human race. These scenes of terror and slaughter were not what they had looked forward to on that night when old Major first stirred them to rebellion. If she herself had had any picture of the future, it had been of a society of animals set free from hunger and the whip, all equal, each working according to his capacity, the strong protecting the weak, as she had protected the lost brood of ducklings with her foreleg on the night of Major's speech. Instead—she did not know why—they had come to a time when no one dared speak his mind, when fierce, growling dogs roamed everywhere, and when you had to watch your comrades torn to pieces after confessing to shocking crimes. There was no thought of rebellion or disobedience in her mind. She knew that, even as things were, they were far better off than they had been in the days of Jones, and that before all else it was needful to prevent the return of the human beings. Whatever happened she would remain faithful, work hard, carry out the orders that were given to her, and accept the leadership of Napoleon. But still, it was not for this that she and all the other animals had hoped and toiled. It was not for this that they had built the windmill and faced the bullets of Jones's gun. Such were her thoughts, though she lacked the words to express them.

Based on the historical context of the Great Purge, which is the best explanation of Orwell’s purpose in writing Animal Farm?

to expose those who failed to prevent massive tragedies and oppression
to explain the process by which most governments begin to collapse
to explain to people the dangers of dictatorships and the loss of personal freedom
to express a need for people to be loyal to their leaders and obey them