The correct answer is the fourth one.
Hoovervilles were shantytowns which appeared during the great depression for unemployed people who were evicted from their homes.
The term "Hooverville" comes from the president in turn during this economic crisis Herbert Hoover, who was therefore widely blamed for it.
as the depression worsened, hundreds of thousands of people settled in hoovervilles, mainly at the skirts of big cities during the decade from 1930 to 1940
In 1932 president Hoover lost the election to Frankling Roosevelt whose new administration helped lift US out of the great depression. Hoovervilles were eventually torn down in the early 1940´s