Answer:
C. Existing States fought over whether or not slavery should be allowed in the new terrotories
Step-by-step explanation:As the united states started expanding the amount of states that were slavery or not had to be kept equal or else there would be lots of tension between the states and they would fight, this was later one of the causes of the civil war. The south wanted westward terrotories to have slavery and the north wanted the oppisite, hope this helps :).