What is a plea bargain and why do some people oppose them?

Congress wanted to "keep the union together despite slavery." what can you most likely infer about this statement about how congress wanted to handle slavery? a congress wanted to make compromises between the states instead of addressing the issue of slavery. b congress wanted everyone to reach agreements on whether to band together against uprisings. c congress wanted everyone to abolish and destroy slavery in the whole of the united states. d congress wanted the united states to immediately deal with the issue of slavery once and for all.