Final answer:
The development of separate, independent city-states was a major effect of the rugged, mountainous geography of ancient Greece. Therefore, the correct option is c. separate, independent city-states.
Step-by-step explanation:
The rugged and mountainous geography of ancient Greece had a significant impact on its civilization, leading to the development of separate, independent city-states. These city-states, known as polis, were formed due to the geographical isolation caused by the mountains. Each city-state had its own government and distinctive culture, with a strong focus on loyalty to one's polis. The Greeks considered themselves civilized and viewed outsiders as barbaric.