The correct answer is C. Ensure voting rights for all men, regardless of race, in the Constitution.
Explanation
The stage after the American Civil War is known as Reconstruction, at this stage, Congress imposed reconstruction laws to unify the entire nation. These constitutional laws obligated the Confederate States (including Texas) to abide by the laws in which it was established that civil rights must be respected for all American citizens including African American freedmen who were granted the right to vote, it was prohibited segregation and they considered themselves free citizens. So the correct answer is C. Ensure voting rights for all men, regardless of race, in the Constitution.
