Then a sheep confessed to having urinated in the drinking pool—urged to do this, so she said, by snowball—and two other sheep confessed to having murdered an old ram, an especially devoted follower of napoleon, by chasing him round and round a bonfire when he was suffering from a cough. they were all slain on the spot. and so the tale of confessions and executions went on, until there was a pile of corpses lying before napoleon’s feet and the air was heavy with the smell of blood, which had been unknown there since the expulsion of jones.

–animal farm,
george orwell

how does orwell create an allegory of the great purge in the passage?

by depicting false confessions and brutality
by creating a character who is a strong leader
by showing a related series of causes and effects
by using imagery when showing scenes of violence