Answer:
The answer is indeed:
1. the pigs shouting angrily at the humans
2. the pigs and humans being indistinguishable
3. the 12 voices all sounding alike
Explanation:
A satire is a criticism against someone's vices, ideas, stupidity etc. made through the use of humor or exaggeration. Satires are commonly used in political contexts. It was also the means through which George Orwell, in his allegorical novella "Animal Farm", criticized the consequences of the Russian Revolution.
The pigs are the characters chosen to represent the Soviet leaders in Russia. Just like those leaders - who came to power having the support of the Russian people, who were craving for equality and justice -, the pigs come to power with the support of the other animals. They preached all animals were equal, and promised to work for the greater good of all. However, as they were corrupted by power and the advantages it brings, the pigs became more and more similar to very humans they once found abominable - the Soviet leaders, too, became more and more like the rulers they fought so hard to destitute.
In the excerpt we are analyzing here, the three lines that best show this satire:
1. the pigs shouting angrily at the humans
2. the pigs and humans being indistinguishable
3. the 12 voices all sounding alike