Look at the graph. Then answer the question that follows. Which of the following accounts for the population trend illustrated in this graph? A) The fear of communism in the United States led to restrictions on labor unions and workers' rights. This led many laborers in northern cities to migrate south in search of agricultural work, taking jobs from African Americans who, in turn, traveled north in search of jobs. B) The onset of World War I created job opportunities in northern cities as demand for industrial goods soared and workers were sent overseas. African Americans, seeking employment and an escape from the violence and discrimination in the Jim Crow South, migrated in record numbers. C) The industrialization of the American West following the completion of the Transcontinental Railroad created many employment opportunities as western cities built up their infrastructure. This, along with a lack of economic opportunities in the South, led many African Americans to migrate westward. D) The end of immigration quotas in the nineteenth century led to the growth of immigrant communities in the South. Their willingness to work for little pay caused a decline in wages in the region, driving African Americans to move northward in search of better employment.