I think it is B. Is led by a president instead of a king
For starts, Jazz music was popularized and it is still popular today since everyone listens to it. Another things is that youth culture started developing independent of their parents culture, and the consumer society focused on satisfying their needs because it was easy to get them to spend money. This is still seen today since capitalist companies exploit the youth all the time by selling them products that they don't really need but are considered "cool". TV and Radio were also created and spread at that time whose influence can clearly be seen nowadays.
