What Was the Changing Situation Facing Some American Cities,particularly in the Northeast

What was the changing situation facing some American cities,particularly in the Northeast?

A) Cities in the Northeast were losing population and jobs to the suburbs,which resulted in a decreasing tax base.
B) While losing population to the suburbs,the tax revenue of most cities increased as factories remained in the city and most workers commuted to the inner city.
C) Population decreased in "Sunbelt" cities as workers moved to find industrial jobs in the Northeast.
D) A large number of African Americans left the city for the suburbs.