Answer: A. The North did not allow slavery, while the South depended on it.
Step-by-step explanation:
While the northern economy depended mostly on manufacturing, the rural southern economy relied on the production of cotton.
Southern colonies´ farm economy could not be sustained without slaves. However, in the northern colonies, the cold weather and infertile soil could not maintain a farm economy, so they came to depend on manufacturing and trade. The clash between these two models led to the war.