In Lord of the Flies, a group of boys find themselves stranded on an island. At first they set rules and try to live in a civilized manner until help arrives. Time passes, however, and they soon begin to fear that help will never come.
As time passes, their rules and orderly way of life begin to slip away. It isn't long before most of them are behaving like animals. They cannot maintain the signal fire, which was necessary in case a ship should pass by them. They never build acceptable shelters, which would provide important protection from the sun and rain. They stop wearing clothes and are practically naked. Their hair and nails grow long. They begin to become quite savage and focused on hunting.
It is not long before actual violence breaks out. First, boys are hurt in a fight. Then, a boy named Simon is actually killed -- accidentally, but still: the damage is done. Then poor Piggy is killed on purpose. All sense of order is lost and the boys have given into their savage side.
Therefore the first statement ("The discovery of orderly civilizations") would not have inspired Golding to write the novel. The boys start out orderly in the beginning of the story but have lost all sense of order by the end.
The second statement -- "international disapproval of British imperialism" -- wouldn't work either. The boys are not taking over the territory of others. Instead they remain on the island and fight for survival. As such, British imperialism would not have inspired Golding to write a tale of savagery.
While the events of the Holocaust and WWII are certainly tragic and terrifying, they are not directly related to the events of the novel. The novel is set on an island and does not have anything to do with the Holocaust.
The final statement best fits the scenario that might have inspired Golding to write Lord of the Flies. An actual shipwreck during which British boys turned on one another accurately describes the events of the novel. One key difference, however, is that the boys in the novel are stranded after a plane crash, not a shipwreck.
