Final answer:
The correct answer is Massachusetts, as it had a robust shipping industry and natural harbors that enabled access to markets and trade, unlike North Carolina and Georgia which lacked these features.
Step-by-step explanation:
The question refers to the natural harbors that provided access to markets in the colonies. From the provided information, we can deduce that the colony known for its natural harbors and as the largest port in the South, significant in the Atlantic slave trade, was Massachusetts. Specifically, Charles Towne (Charleston), South Carolina's port notoriously played this role. Conversely, North Carolina was known for its difficult coast and lack of natural harbors. Georgia, while known for Savannah, was primarily a buffer zone against Spanish Florida and did not rely on natural harbors the same way Massachusetts did.
Therefore, the correct answer would be Massachusetts, considering it had a strong shipping industry due to its excellent harbors and was part of the New England colonies engaged in whaling, fishing, and shipbuilding, with a focus on maritime activities.