The correct answer is - shanty towns of temporary homes for homeless people.
The ''Hoovervilles'' were shanty towns that were made for the homeless people, in order to provide them with a temporary shelter. This was a result of the Great Depression, when lots of people came to become poor because they were left without a job, or their incomes were very low. The ''Hovervilles'' were named after the American president during whose reign they were built, President Hoover, who was also the one blamed for the Great Depression at the first place.