The correct answer is:
B. Tobacco exhausted soil, so that planters often had to find new land.
Explanation:
One of the biggest activity for the economy of American Colonial times was the plantation of tobacco, mostly in the Chesapeake Bay and North Carolina.
Tobacco plantations brought a wealthy economy for the colonies but it came with a lot of dangers and problems, one of them was that after three years of plantation, tobacco exhausted the soil of its nutrients. So colonists had to look for more fertile land and ended up forcing Native Americans to move from their lands in exchange of goods.