One of the Reasons That Modern Cultures Differ So Greatly

One of the reasons that modern cultures differ so greatly from traditional cultures is that

A) more money is available and therefore newer cultures are more market-based.
B) the structure of modern urban life has drastically changed the frequency of different kinds of social relationships.
C) modern societies are "smarter" and have figured out better ways to live.
D) modern urban dwellers have a fundamentally different nature than do members of traditional cultures.