The right answer is C) Natural harbors provided access to markets.
The geography influenced the economic development of New York, Boston, and Charleston, because they were all ports and this helped with trading. Mos t of these coasts were useful to be communicated with the world.
There were many ships coming in and coming out and also due to this, many communities started settling there and towns started booming due to the growing amount of people.
For example, Boston has played a lessening role in national life since the early 20th century, it has remained the focal point of what may be the most diversified and dynamic combination of educational, cultural, medical, and scientific activities in the United States.
And the most important case is in New York. For example, its International shipping has always been a major part of the city's economy because of New York's natural harbor.