The correct answer to this open question is the following.
Although you forgot to attach the options for this question we can say the following,
The practice that was a means the federal government used to safeguard blacks' civil rights during congressional Reconstruction was sending soldiers to the South to enforce antidiscrimination laws.
Let's remember that the main goal of President Lincoln’s Reconstruction plan was to help the nation heal and move past the war quickly.
What President Lincoln always wanted was to maintain the unity of the country. So when it came to the time of Reconstruction after the Union's victory in the Civil War, Lincoln made things easy for the South to do Reconstruction at their own pace. What Lincoln required from the Souther states was for them to accept the 10% plan that established that a southern state would be accepted into the Union if 10 percent of citizens pledged the Oath of Allegiance.
