Final answer:
In ancient Greece, democracy notably in Athens, promoted civic engagement among citizens, while warfare led to periods of centralized power but also spurred an era rich in culture, literature, and philosophy.
Step-by-step explanation:
War and democracy played significant roles in shaping societies in ancient Greece. Democracy, notably in Athens, encouraged civic participation by allowing free adult males to engage in the political process. This promoted civic engagement and included rich and poor alike, contributing significantly to Ancient Roman and European political thought. On the other hand, the constant warfare among Greek city-states, especially during the Greek Classical period (500-323 BCE), led to certain forms of centralized power. Tyranny and oligarchy are examples where power was consolidated in the hands of a few. However, war also had the unintended effect of spurring cultural development as evidenced by the lasting achievements in art, literature, and philosophy during the Classical Age, despite occasional setbacks due to ongoing conflicts.
Therefore, it is clear that democracy promoted civic engagement (option c), rather than isolationism, and wars could lead both to centralized power (option b) and to periods where cultural development flourished despite, or even because of the turbulence of the times.