The correct answer is A) allowed some states to continue to use slave labor.
The other options of the question were B) opposed the Thirteenth Amendment to the Constitution. C) did not allow freed slaves to join the U.S. military. D) prompted foreign countries to support the Confederacy.
The reason many people MOST LIKELY attacked the Emancipation Proclamation was that it allowed some states to continue to use slave labor.
The Union's Army victory in the Battle of Antietam gave Lincoln the strength and support needed for the issuance of the Emancipation Proclamation. With the victory of the Union Army over the Confederates, President Abraham Lincoln felt confident enough to write the Emancipation Proclamation that freed slaves in the territories of the south. The preliminary Emancipation Proclamation was issued on September 22, 1862. However, one of the things that did not appeal to the people was that it allowed some states to continue to use slave labor.