A foil is a character that is the opposite of the protagonist, but not necessarily in a bad way. It only means they have opposite qualities--it does not mean that they are the antagonist of the main character. Antithetical character are normally their "enemies"--they are the antithesis. Think antithesis of the main character.
So you can review what you've written and correct your mistakes.
The answer is A. Precise language uses specific words and phrases to help the reader "see" what is being described, which A does well.
Answer:
Reconstruction- the term used for the post-Civil War
period in the South
Sharecroppers- people who worked the fields in
exchange for a share of the crops
1870- African American men given the right
to vote under the 15th Amendment
the end of the Civil War
1865- The end of slavery and the passing of the 13th amendment (not seeing any options for it but)