How did South Carolina’s decision to secede affect Louisiana and the rest of the southern states? A) It had an insignificant effect on other states because they had voted to secede prior to South Carolina’s decision.
B) It caused other states to feel pressure to make a decision on the issue of slavery. C)It made Louisiana and other southern states remain undecided and feel South Carolina moved too quickly.
D) It led to most southern states experiencing an increase in outbreaks of violence over the issue.

Im not 100% sure so if im wrong im sorry i think its B

Explanation:

When South Carolina seceded from the Union, the action was the first domino to fall so to speak. Emboldened by the South Carolina decision, the other states that would eventually make up the Confederate States of America- Virginia, North Carolina, Georgia, Florida, Alabama, Mississippi, Louisiana, Texas, Arkansas and Tennessee- followed this example and broke away from the U.S.

the monroe doctrine is the best known u.s. policy toward the western hemisphere. buried in a routine annual message delivered to congress by president james monroe in december 1823, the doctrine warns european nations that the united states would not tolerate further colonization or puppet monarchs.

fairly positive it is 4