The best analysis of how migration can change culture among the provided options is:
Migration can spread cultural ideas to destination regions, but in recent eras it has had more of an effect on source regions.
This option acknowledges that migration can influence both destination and source regions, reflecting the complexity of cultural exchange and adaptation that occurs through migration processes. It captures the idea that while destination regions may adopt new cultural elements, source regions can also experience significant cultural shifts as migrants return or maintain connections.