How did president lincoln's emancipation proclamation affect the institution of slavery? a. it freed only the slaves in confederate territory. b. it freed all slaves within the united states' borders. c. it freed only the slaves in the border states. d. it freed all slaves north of the mason-dixon line.

A. freed only slaves from confederate territory. See the issue here was that border states, even Northern ones didn't have the laws or drive to change the slavery stance "law wise". Even though we can all hypothesize that the issue of slavery didn't really reach to a changing revolution till the later 1900's.