Chocolate is a typically sweet, usually brown food preparation of cacao seeds, roasted and ground, and often flavored with vanilla. It is made in the form of a liquid, paste, or in a block, or used as a flavoring ingredient in other foods. Cacao has been cultivated by many cultures for at least three millennia in Mesoamerica. The earliest evidence of use traces to Mexico and Guatemala, with evidence of chocolate beverages dating back to 1900 BCE. What is the main idea of this passage?

A) Chocolate is actually often flavored with vanilla.
B) Chocolate was first consumed in Mexico and Guatemala.
C) Chocolate can be served in the form of a liquid, paste, or in a block.
D) Chocolate is a sweet brown food that has been eaten by humans for over three millennia.