Which sentence in as example of a pun?

a) rome was not built in one day, and greece was built in three.
b) raul kept reminding justin that he should not judge a book by its cover.
c) never bite the hand that feeds you.
d) the cow stood in udder amazement when she unable to produce milk.

Read the passage from animal farm. 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. what was most likely orwell’s purpose for writing this passage? to show that clover is more sensitive to violence than the others to remind readers of major's speech and the original rebellion to present napoleon as a cruel leader unworthy of the animals’ support to represent misled followers and their dashed hopes for better lives