During the 19th century, american society became increasingly:
a) rural b) homogeneous c) heterogeneous d) non-industrial i think the answer is either a or d but i just can not find it in my book me if you can. i have even googled but nothing.

Its c)heterogeneous. In the 19th century, after the 2nd industrial revolution.,Tracks of railroads connected different states opening trades, immigration of European people to America, migration of people from rural to urban for job opportunities, trading in Atlantic . These only shows that in in 19th century there is mixed of people, culture, and goods, and languages.  

The answer would be advertising.