Final answer:
The primary purpose of "race records" was to restrict African American voting rights, as part of larger strategies like the white primary, grandfather clauses, and manipulated literacy tests—tactics aimed to maintain white supremacy.
Step-by-step explanation:
The primary purpose of "race records," kept by the census during the post-Reconstruction era in the South, was c) to restrict African American voting rights. These records were part of a larger set of tactics implemented by Southern states to prevent African Americans from wielding political influence through voting. Along with the poll tax and literacy tests, the use of these records was undergirded by racial discrimination and served to uphold white supremacy by undermining Black voters' access to the polls.
Various subversive strategies were utilized to silence the African American vote, including the implementation of the white primary, grandfather clauses, and the manipulation of literacy tests. Despite some African Americans overcoming these barriers, the system was structured in such a way that their votes had minimal impact. The culmination of the civil rights movement and the subsequent Voting Rights Act of 1965 marked the end of these discriminatory practices, allowing for a more inclusive democracy.