To form a comprehensive theory explaining the Great Atlantic Migration, the most relevant options would focus on the push and pull factors influencing migration. Among the provided responses, the following would be most appropriate:
- political push factors in Europe due to governmental instability - This reflects conditions in Europe that drove people to leave.
- economic push factors in Europe resulting from crop failures - This also explains why people would migrate, highlighting failures in their home countries that forced them to seek better opportunities elsewhere.
- environmental pull factors in the U.S. held a desirable climate - This indicates a positive factor attracting migrants to the U.S.
- economic pull factors in Europe due to industrial growth - While this option does mention economic factors, it seems to focus on the conditions within Europe rather than those enticing migration to the U.S.
Given that the question asks for a theory explaining the Great Atlantic Migration as a whole, the first three responses about political and economic push factors in Europe along with the environmental pull factors in the U.S. would best describe the phenomenon. In particular, the combination of political and economic push factors from Europe and environmental pull factors in the U.S. provides a holistic explanation for the migration.
Thus, if you had to select one for a summarizing theory, the best option would likely be:
- political push factors in Europe due to governmental instability or
- economic push factors in Europe resulting from crop failures
(Depending on which aspect you wish to emphasize). But ideally, combining the push and pull factors allows for a more nuanced understanding of the migration.