Explain why the Battle of Antietam had a profoundly important impact on the war.

A) The Battle of Antietam marked the beginning of foreign intervention in the war, shifting the balance of power.
B) The Battle of Antietam resulted in a decisive Confederate victory and the capture of Washington, D.C.
C) The Battle of Antietam prompted the Emancipation Proclamation and prevented European recognition of the Confederacy.
D) The Battle of Antietam had little impact on the war, as it was a minor engagement with limited consequences.