It was "Mitchell Palmer" who was the attorney general under President Wilson who led a witch-hunt to round up communists in the 1920s, since these were known as the "Palmer Raids".
There exist a similar question which goes like,
A jury trial ___.
The remaining items in the question above happen to be the choices. The answer to this item is letter "A.. happens at the trial or district court level."
Ending slavery means it will stop for sure, mean while ending the slavery trade means you won't be making more trades but slavery still exist.
Hope this helps! :)