The Great Atlantic Migration can be explained by a combination of various factors, but out of the options provided, the most accurate is:
economic push factors in Europe resulting from crop failures
This indicates that many individuals migrated due to a lack of resources and opportunities caused by agricultural difficulties, which drove them to seek a better life in the U.S. The other factors do play a role, but they may not encapsulate the driving motivations of the migration as effectively as the economic push factors resulting from crop failures.