The correct answer is C. The proclamation only applied to the Confederacy
Step-by-step explanation:
The Emancipation Proclamation was approved in 1863, and through this, President Lincoln ordered slaves needed to be freed in the Confederacy states, which were Southern states in rebellion. This caused slaves to be freed in areas were the Union (Northern states) had control; however, slavery continued in areas in the rebel states and some border areas. Because of this, in 1865, the Thirteenth Amendment to the Constitution was ratified, and through this slavery was officially abolished in all the states of the United States. Thus, a national law was needed because " The proclamation only applied to the Confederacy."