The correct answer is B.
In the aftermath of the US Civil war, during the so-called Reconstruction Era, the 13th, 14th and 15th Amendments to the US Constitution were ratified in 1865, 1868 and 1870 respectively. These three are actually known as the Reconstruction Amendments.
- The 13th Amendment abolished slavery and banned discrimination in terms of race, color or previous condition of servitude.
- The 14th Amendment granted the US citizenship to black citizens and former slaves who were not enjoying it yet and guaranteed equality of rights for all US citizens.
- The 15th Amendment considered illegal that any federal or state goverment entity preventing any US citizens from exercising their voting rights.