The correct answer is D) The 1893 Columbian Exposition was very popular.
The statement that best represents the main idea of this source is "The 1893 Columbian Exposition was very popular."
This is the correct answer because the excerpt tries to convey the idea that despite the United States was a young nation with a population of just 65 million people, the 1893 Columbian Exposition attracted 27 million people from all over the world, a fact that made the exhibition to be a very popular one.
This meant that although a young nation, the United States generated great expectations in different parts of the world to know its culture, customs, political and economic advances, and social organization.
