I'm not positive, but I believe the answer would be the last one.
Young, light skin, female virgins were the most frequently bought slave due to their popularity among countries in the near East.
Light Skin women were seen as more beautiful and virgins were thought to be more 'pure'
These young women would first work in the households of rich people. If they were popular they would become a concubine and in many cases eventually a wife of their master.
The Wade-Davis bill required that 50% of a state's white males take a loyalty oath to be readmitted into the Union. States were also required to give voting rights to blacks.