Final answer:
The correct answer is option B) The federal government's protection of Black voting rights.
Step-by-step explanation:
Throughout Reconstruction and into the 20th century, Democrat-led states employed a variety of strategies to disenfranchise African American voters. These tactics included literacy tests, poll taxes, stringent residency requirements, and outright violence. The Democrats struggled to completely disenfranchise blacks due to federal government's protection of Black voting rights, and also the resistance of Republican Party which, during Reconstruction, supported extending voting rights to African Americans.
Furthermore, civil rights activists and organizations like NAACP played a pivotal role in challenging discriminatory practices, leading to landmark Supreme Court cases such as Smith v. Allwright which ruled denying blacks the vote in primary elections unconstitutional. In spite of these challenges, Southern states effectively excluded many African Americans, and some poor whites, from voting.
Voter suppression tactics, such as gerrymandering and fraud alongside violent intimidation by groups like the Ku Klux Klan, significantly reduced the level of black voting. However, the collapse of Southern Populism and claims of "negro domination" incited white Southern Democrats to reinforce voter disenfranchisement through "reforms" and violence, perpetuating a cycle of poverty and division among poor whites and blacks. It wasn't until the civil rights movement culminated in the passage of the Voting Rights Act of 1965 that there was a substantial push against these oppressive tactics, resulting in improved voter registration and empowerment for African American voters, including the creation of majority-minority districts.