What did The Missouri Compromise, Compromise of 1850, and Kansas-Nebraska Act have in common?

a) They were ordinances that outlawed slavery across the United States.

b) They were treaties with European nations that increased westward expansion.

c) They protected the rights of Native American people throughout the west.

d) They were national laws to balance power between slave and free states.

d) They were national laws to balance power between slave and free states.