A historian notes that many African Americans moved from southern rural areas of the United States to large urban centers farther north between 1910
and 1930. He hypothesizes that the availability of high wages in northern
factories was the fundamental cause of this population shift. Which two
themes would this historian focus on as he researches his hypothesis?
A. The themes of American and national identity, and of work,
exchange, and technology
B. The themes of politics and power, and of culture and society
C. The themes of migration and settlement, and of America in the
world
D. The themes of migration and settlement, and of work, exchange,
and technology