The african american population of cities in the northern states during the

The African American population of cities in the northern states increased during the American Revolution.

The population increased because great migration increased at that time. African American people have a great role in America Revolution, black and white people fought together even in three musicians with General Washington at Yorktown, and one of them was black.  

c it says nothing about connecting those 2 seas.

the option which was not a function of missionaries in the northwest was the first one - they established posts for trading furs and other goods.

missionaries were sent around the world to spread religion and their knowledge and others - they were not merchants who sold furs and other goods.