The cities of new york, baltimore and philadelphia began to become wealthy in the late 1600s because of what economic activity

This question is incomplete, here´s the complete question.  

The cities of New York, Baltimore, and Philadelphia began to become wealthy in the late-1600s because of what economic activity?

A) trading

B) slavery

C) rice farming

D) tobacco farming

A) trading

Explanation:

British Mercantilism was a key element for the colonial cities in the United States to prosper. The biggest cities took an especific economic role in the trade with Europe. While New York most important trade were flours and furs, Philadelphia traded on meat, wheat, and lumber,  and Baltimore eventually prospered by developing the flour-exporting trade.

the foundation of greek city-states: following the fall of the mycenaean civilization in the 10th century bc, the area surrounding the empire went through its own mini dark ages. answer and explanation