Why did Lincoln's Emancipation Proclamation only free slaves in the South?

A. Lincoln wanted slavery in the border states to continue because farming in those states helped the Northern economy
B. Lincoln believed that northern slaves were treated better than southern slaves, so they did not need to be freed
C. Lincoln believed he only had the authority to free slaves in rebelling states as a military tactic

Ifound the exercise on the internet. attached is the list mentioned above.in order for a compound to be considered optically active it can't have any axis or plan of symmetry. the molecule  shouldn't also  be superimposable on its mirror image.with such considerations, the compounds that are optically active are: -third compound on the first image is optically active; -second and third compound from the second image are optically actives.