Black officeholders during reconstruction: - were extremely rare. - were entirely carpetbaggers and scalawags. - ensure a degree of fairness in treatment of african-american citizens. - were limited to local offices. - demonstrated that whites had lost all their political power in the south.

Option: helped ensure a degree of fairness in treatment of African-American citizens.

Explanation:

Before the Civil War in America, the African American allowed to vote in the North but never selected in the office. During the Reconstruction period, the African Americans not only allowed to vote but to elect in the offices who saw after the needs and the rights of the African American communities. It is expected that about two thousand African Americans held office during this period.

the answer is option a.