"the pre-world war i period saw political and economic reform and a volatile economic climate that heralded a new era for the united states. during this period, immigration was a major force, with nearly 9 million immigrants entering the united states between 1900 and 1910. later, the country became embroiled in the great war, which required the federal government for the first time to attempt to place significant controls over the economy. after the transition from the war, the country experienced an extended period of prosperity that ended in 1929 and when the country entered the great depression. the depth of the depression would ultimately provide the catalyst for a change in how workers viewed self-sufficiency that would, in turn, give way to changes in how american workers were paid." courtesy of the united states bureau of labor statistics

how does this introductory paragraph organize the information and ideas presented in the text that follows?

a.
it provides background information for the text.

b.
it explains the events that led to the great depression.

c.
it offers a pre-summary of the main ideas that follow in the text.

d.
it suggests how world war i negatively effected the economy of the country.