Answer :
b is correct .To preserve & restore the Union, which was his central sworn
duty as President. Although he also wished very much to see the end of
slavery, he only pursued that goal when it aligned with the one of
restoring the Union.
The correct answer is:
B. To preserve the Union
Explanation:
After Abraham Lincoln's victory in the election of 1860, Southern states began seceding from the Union because they felt their interests were no longer represented by a President that wanted to stop slavery while their main economic activities relied on the work performed by slaves, so they created the Confederate States and the Civil War begun.
The main goal of Abraham Lincoln on the Civil War was to preserve the Union, during his campaign he stated that slavery shouldn't be expanded in the United States, meaning that new states would be added as free states, the end of slavery became a goal during the Civil War.