Final answer:
The geographic characteristic that most influenced the Southern Colonies was (option C) large ports that promoted international trade.
Step-by-step explanation:
The geographic characteristic that MOST influenced the Southern Colonies was (option C): large ports that promoted international trade.
The Southern Colonies, including North Carolina, South Carolina, and Georgia, had a significant amount of coastline and access to large ports. These ports allowed for the establishment of international trade routes, which were vital for the economic success of the colonies. In addition to trade, the ports also facilitated the import and export of goods, including slave labor.