c) slaves. Explanation: After the Emancipation Proclamation of 1865, the Unionist North was reunited with the Confederate South, but Lincoln (and later McKinley when Lincoln was assassinated) took 10 years to fully reinstate the United States of America, and this was one interim measure. Ultimately, one vote equaled one vote, regardless of color (but not gender, which took another 50 years with the Women’s Suffrage Act). Hope that helps!