<em>B. Soviet building of the Berlin Wall.</em>
Explanation:
After World War II ended, Germany got split up amongst the Allied powers. The United States, France, and Great Britain got West Germany, while the Soviet Union got East Germany.
The Soviet Union centered around communism, so East Germany had a communist government. Many Germans realized they did not want to obey and live under this government and wanted to flee. East Germans started leaving and moving to West Germany.
Over time, East Germany started to become fearful that too many people were leaving and decided they needed to do something about it. They built the Berlin Wall that was heavily guarded and hundreds of people ended up dying trying to get through.
This was the first cause of tension between the Soviet Union and President Kennedy. Both John F. Kennedy and Ronald Reagan gave speeches about the wall and how horrible it was.
Slavery made it to where families were split apart, and were unable to keep in contact. Mothers couldn't tend to their children enough, and often children were made to also be slaves. Children also got beat, and were unable to eat the correct amount of proportions to stay healthy, children started "Helping" the parents at a young age.
Reconstruction refers to the period immediately after the Civil War from 1865 to 1877 when several United States administrations sought to reconstruct society in the former Confederate states in particular by establishing and protecting the legal rights of the newly freed black population. Historians consider Reconstruction to be a total failure as the former Confederate states did not recover economically from the devastation of the war and the Black population was reduced to second class status with limited rights enforced through violence and discrimination.