Answer: This answer involves C. sectionalism. Due to many differences between the Northern and Southern states, segregation and slavery were major issues. Most wanted to escape to freedom in the North, while others were held captive in the South. Disputes come from the idea of wanting slaves to have their own territory in states like Pennsylvania, but because the North and South couldn't come to an agreement, any slave who planned on escaping had to move to Canada, where slavery was pretty much banned or annexed.
Hope this helped!