Probably D saying all the others make no sense. <span />
I would say D. Restrict it because the north of the U.S. had no slavery while the south did so they kinda restricted it to only being allowed in the south.
The least common denominator of them is 75:
15, 30, 45, 60, 75, 90, ...
25, 50, 75, 100, ...
Five fifteens fit in 75 and three twenty-fives fit in 75, so we have to multiply the first fraction by 5 and the second one by 3:
10/75
12/75
It means that the second one is bigger by 2/75.
