What event in u. s. history might dr. king be referring to when he says, "the negro's basically mobility is from a smaller ghetto to a larger one"?

are these the benchmarks questions?

for the united states of america, 1945 to 1964 was a time of high economic growth and general prosperity. it was also a time of confrontation as the capitalist united states and its allies politically opposed the soviet union and other communist countries; the cold war had begun.

explanation:

the answer is c, all the other options are things they are known for.

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