SAT English Practice Question

The author provides a history of the process of how the United States obtained the Louisiana Purchase. The author also states that the Louisiana Purchase was a key moment in American history because it doubled the size of the United States. The author argues that the Louisiana Purchase was also a pivotal event because it helped to open up the western part of the United States to settlement. The author concludes by saying that the Louisiana Purchase is a significant event in American history. What is the main idea of this passage?

1. A.The Louisiana Purchase doubled the size of the United States, which helped to open up the western part of the country to settlement.
2. B.The United States obtained the Louisiana Purchase through a complex series of events.
3. C.The Louisiana Purchase had a significant impact on American history.
4. D.The author provides a chronological account of the Louisiana Purchase.