Which is the best explanation for why the northern economy was based on industry during the antebellum period?

The Antebellum Period is a period in which industrialization was on the rise in the North. Whereas there was a boom in cotton in the South with the introduction of the cotton gin. The South relied more on slavery for cotton production, the North was more reliant on labor. The North had also exhausted a lot of the land by this period for agriculture use and therefore it was in its own economic interest to industrialize rather than rely on agriculture.