The correct answer is:
D. It freed all slaves in states rebelling against the Union.
The Emancipation Proclamation, issued by President Abraham Lincoln on January 1, 1863, declared that all slaves in the Confederate states (those in rebellion against the Union) were to be set free. However, it did not grant citizenship or voting rights to freedmen and freedwomen, nor did it outlaw slavery throughout the entire United States (that was accomplished later by the 13th Amendment).