What Was The Mason-Dixon Line

The Mason-Dixon Line was created in the 1760‘s as a survey line to settle a property dispute between the colonies of Maryland and Pennsylvania. Originally the Mason-Dixon line was a boundary, in the late 18th century and the early 19th century the line developed into the boundary between Free and Slave states. The Missouri compromise failed to ease tension over slavery, which lead to more compromises and eventually the Civil War. The key compromises were:
A. Missouri would be admitted to the Union as a Slave state.
B. Maine would be admitted to the Union as a Free state.
C. A boundary line following the southern border of Missouri at 36 degrees 30 minutes North Latitude would be extended across the territory of Louisiana.
D. Slavery would be