Why was the country so divided over tariffs, slavery and states’ rights?

they had leaders that wanted to take national control.
they promoted their regional interests.
they wanted the federal support of their area.
they planned to make the country into one voice.

Answer is Option B: They promoted their regional interests.

Explanation:

The biggest issues that divided the nation was their views on the Constitution.

The North wanted a strong national government, having supreme powers and authority. But, the South supported States' rights. They said that states could nullify the federal laws in case they did not agree with them. Both of them also had different opinions on tariffs. On one hand, North wanted high taxes to protect their industries from foreign competition. South, on the other hand,  were against tariffs. They were more self sufficient than the North ones.

North viewed slavery as evil and inhuman while South said slavery was necessary for their way of life and they even cared for the slaves.