The correct answer is - D. popular culture.
Lots of folk cultures around the globe are in threat of going extinct and be only a thing of the past, and that is due to the acceptance of the popular culture, mostly by the younger generations.
By accepting the popular culture, the younger generations are trying to fit in in the world and be trendy, but that also means that they are abandoning their own traditional, folk culture. By not practicing it, and not appreciating it, very quickly the folk cultures around the world will be gone forever.