Which was NOT a major factor contributing to the diverse population found in the Middle Colonies?

These are the options for the question:

a) more african slaves were brought there due to large plantations.

b) more religious tolerance existed, especially among the quaker colonies.

c) more economic opportunities were available due to trade and navigable rivers.

d) more land was mad available to immigrants and not just to the landed aristocracy.

And this is the correct answer:

a) more african slaves were brought there due to large plantations.

Explanation:

The Middle Colonies were New York, Pennsylvania, Delaware and New Jersey. These colonies had a great degree of diversity because they had great religious freedom and economic opportunities.

Not a lot of slaves were brought to these colonies though. The climate did not favor the creation of large plantations like in the south, and the few slaves that were imported were mostly port workers and domestic workers.

what are the choices?