Final answer:
The Civil Rights Act of 1866 was passed by Congress in response to the widespread antiblack violence and the Black Codes in the South, which threatened the rights of African Americans.
Step-by-step explanation:
The event that spurred Congress to pass the Civil Rights Act in April 1866 was c. The eruption of antiblack violence in various parts of the South. This violence was seen in the enactment of the Black Codes and was influenced by the White supremacist ideology prevalent in the aftermath of the Civil War. congress felt that further action was necessary beyond the Thirteenth Amendment, which had abolished slavery, to ensure the rights of African Americans were protected. This led to the passage of the Civil Rights Act of 1866, which aimed to counteract the Black Codes by affirming that all persons born in the United States were entitled to the full protection of the Constitution, regardless of race, and allowed federal intervention to protect citizens' rights when necessary. Despite President Andrew Johnson's veto, Congress overrode the veto, marking a significant step in the reconstruction era.