Answer:
The mountains caused isolated communities to form separate governments.
Explanation:
This is the correct answer because geographical isolation led to creation of many city-states in Ancient Greece, with different forms of governments. Those governments varied. Some were monarchies, some democracies, some oligarchy, etc.
First option is wrong, because unique Empire was never formed in Greece.
That is why second option is also wrong, as cities were never united, except in military alliances.
The third option is also wrong because regional governments were not known to Greeks in that period.
