An american colonist who supported the british side during the american revolution or a supporter of the conservative party
The answer is a) the division of germany.
Even after the unification, that gradually happened between 1815-1871, the conflict still continued mainly because of quite major regional and ethnic differences. Since Italy was separated for quite a long time, different traditions, views on politics, and much more appeared within these societies. If you take a closer look at the image below, you will see how many different societies lived separately. You could only imagine how diverse that area was.