A counterclaim is a reason someone disagrees with a position. Option A is correct.
Counterclaim is denined as a statement that someone makes in response to a statement that has been made by someone else, and that is different from it.
In terms of essays, counterclaims are understood to be the opposite of the argument, or the opposing argument that will be develope with examples that support it in order to prove that this point of view or position is correct in opposition to another one.
Southern states started to pass Jim Crow laws after Reconstruction since that was the best way to guarantee the liberated slaves wouldn't affect or adjust Southern culture notwithstanding their rights under the 14 Amendment.