According to the resource, what historical event to spark the harlem renaissance and how?

World War I caused a shortage of workers in northern factories. Many African American field workers decided to move north to pursue new, better jobs. One of the areas that drew many African Americans was Harlem, a neighborhood in New York City. Concentrated into one urban location, these African Americans shared their artistic talents and sought an outlet for self-expression as a means of achieving equality. Their combined efforts led to the development of the Harlem Renaissance.

can you explain a little further maybe give multiple choice? ?