Christina is writing a paper about the early history of the United States. She has come across the following quotation from American Leaders and Heroes, written by Wilbur Fisk Gordy: The famous state paper, in which Lincoln declared that the slaves were free in all the territory of the seceded States whose people were waging war against the Union, was called the Emancipation Proclamation.

What is the best way to use this excerpt in her essay without plagiarizing?

A. The famous state paper, in which Lincoln declared that the slaves were free in all the territory of the seceded States whose people were waging war against the Union, was called the Emancipation Proclamation.
B. The famous state paper, in which Lincoln declared that the slaves were free in all the territory of the seceded States whose people were waging war against the Union, was called the Emancipation Proclamation. (Gordy).
C. The Emancipation Proclamation was a document "in which Lincoln declared that the slaves were free in all the territory of the seceded States whose people were waging war against the Union."
D. The Emancipation Proclamation was a document "in which Lincoln declared that the slaves were free in all the territory of the seceded States whose people were waging war against the Union" (Gordy).