The statement that best describes the federal government’s response to racial violence in the South in the late 1800s is: "The federal government had no response because it had pulled troops out of the South in 1877, leaving African Americans unprotected."
After the withdrawal of federal troops following the Compromise of 1877, the federal government largely stepped back from enforcing protections for African Americans in the South, leading to increased racial violence and the establishment of Jim Crow laws.