In 1870, to the fifteenth amendment, southern black men
a. voted for the first time.
b. took charge of the senate.
c. received free government land.
d. produced their own reconstruction plan.

The best answer is  A.

The 15th Amendment to the constitution granted African American men the right to vote by declaring that the "right of citizens of the United States to vote shall nt be denied or abridged by the United States or by any other state on account of race, color or previous condition of  servitude."
 Although ratified in on February 3, 1870, the promise of the 15th Amendment was not fully realized until almost a century  later.
Through the use of poll taxes, literacy tests and other means, the Southern states were able to keep African American people from voting.

In 1870, thanks to the Fifteenth Amendment, southern black men
A. Voted for the first time
Hope this helped!