Among the options provided, radicalization is a cultural trait that can operate as a centrifugal force in a country. Radicalization often leads to division and conflict within a society, as it can create deep-seated ideological divides and potentially incite violence or unrest.
On the other hand, multiculturalism and popular culture generally promote unity and integration, while diffusion refers to the spread of cultural elements, which can also foster connection rather than division.