Can somone please help with this?

Heres the map

http://img391.imageshack.us/my.php?image=eastcoastsf3.gif



This question refers to the passage and the map. Along the fall line, waterways from higher inland areas drop to lower coastal plains either as waterfalls or a series of rapids. Many important manufacturing and harbour cities grew up along the fall lines. The fall line of the east coast of the United States is shown on the map. Which of these is the best explanation of why cities developed along the fall line?



1.)Flatter land below the fall line is better suited to farming.

2.)Early colonists stayed on the coast of the Atlantic Ocean, and their towns became modern cities.

3.)People prefer to live close to mountains, and mountains that are too rugged to live in start at the fall line.

4.)A settlement close to the river has a steady supply of water for farming.

5.)Ships could not go farther inland so trading was done at the fall line, and the waterfalls provided a source of powerCan somone please help with this?
4 MAKES SENSE as water is for farming and travel