What did the Missouri Compromise, the Compromise of 1850, and "Bleeding Kansas" have in common?

Responses
A They were all vetoed by President Abraham Lincoln.They were all vetoed by President Abraham Lincoln.
B They helped Abraham Lincoln win the Election of 1860.They helped Abraham Lincoln win the Election of 1860.
C They all dealt with the expansion of slavery into the western territories.They all dealt with the expansion of slavery into the western territories.
D They were permanent solutions to the conflict between the North and South.

C They all dealt with the expansion of slavery into the western territories.