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 the dynamic nature of culture and how migration facilitates the exchange and diffusion of cultural ideas both in the regions people leave (source regions) and the regions they move to (destination regions). It recognizes that while destination regions are influenced by incoming cultural elements, source regions can also experience significant changes due to the loss of people and their cultural contributions.