Why did the middle colonies have the most diverse populations in colonies begin ?

There was more diversity in the Middle Colonies because of many reasons.

1. They were in the center! This simply fact allowed ideas and immigrants to arrive to these middle colonies. Benjamin Franklin, for example, rose from the Middle Colonies, and gained the respect of the colonies and the English Dynasty. 

2. Religions from all over the place arrived at the nucleus, the Middle Colonies. Mennonites, Native Americans, Quakers, and many other religions all flooded to the middle of the 13 colonies.

3. The climate and fertile land often attracted immigrants from other places. Often called "breadbaskets," the middle colonies focused on cultivating wheat and selling bread to other regions around the world. 

4. Served as the "middle ground" between the North and South. The North and South were the two regions with the most disagreements, and the Middle Colonies were often a balance of both.

5. Included many well-known cities! New York, New Jersey, Pennsylvania and Delaware were all part of the Middle Colonies, and they still remain to be a huge influence in our modern nation.

The answer is b