What Was the Phenomenon of "White Flight" in the 1950s

What was the phenomenon of "white flight" in the 1950s after the Second World War?

A) It was a type of housing discrimination shown toward African Americans that soon stopped when the federal government banned it and funded many mixed communities.
B) It was the movement of poor whites fleeing the South for jobs in big northern cities since the economic boom following the war never arrived in the South.
C) It was the return of white Americans to the rural countryside, as farming became the most lucrative occupation in part due to the lack of food Americans had during the war.
D) It was the movement of many whites to suburbs in response to the migration of African Americans from the rural South to northern cities in search of better opportunities after the war.
E) It was the movement of Puerto Rican Americans to Puerto Rico because there was a shortage of housing in northern cities after large numbers of white Americans moved there after the war.