Final answer:
Urban decentralization did not contribute to Black migration to the North; factors such as post-WWII industrial growth, the decline of Southern agriculture, and farm mechanization drove the Great Migration.
Step-by-step explanation:
The subject in question pertains to the factors that did not contribute to Black migration to the North. Among the choices provided, urban decentralization is the factor that did not contribute to Black migration to the North. The growth of industrial production after WWII, the decline of Southern agriculture, and the mechanization of farms were all significant contributors to the migration. Urban decentralization typically refers to the spreading out of a city and its suburbs, which may lead to the decline of central urban areas, but it does not relate directly to the migration patterns of African Americans during the period mentioned.
The Great Migration was largely driven by the desire for better economic opportunities, which included higher wages available in Northern industries and the decline of the Southern agrarian economy. The invention of the mechanical cotton picker decreased the need for manual labor on Southern plantations, resulting in many African Americans losing their jobs. This, combined with the appeal of higher wages, better education, and less legal segregation in the North, encouraged the move.