Read the following paragraph from the section "Seeking New Sources of Labor."
With the ideal climate and available land, property owners in the southern colonies began
establishing plantation farms for cash crops like rice, tobacco, and sugar cane. These enterprises
required increasing amounts of labor. To meet the demand, wealthy planters turned to slave
traders, who imported even more kidnapped Africans to the colonies, the majority from West
Africa. More Africans were imported and had children, thereby increasing this human "inventory."
A new industry was born: the slave auction, where humans were inspected like animals and sold
to the highest bidder.
What is the MAIN reason the author includes this paragraph in the article?
(A) to list the cash crops that were grown using slave labor
(B) to introduce the positive qualities of the South's climate and land
(C) to contrast the conditions of slaves with indentured servants
(D) to elaborate on the causes and growth of the slave-based economy