The most accurate response is:
South Carolina favored ratifying because the new constitution posed no threat to slavery and offered regulation of foreign commerce.
This response highlights two key considerations for South Carolina: the preservation of slavery, which was vital to their economy and social structure, and the potential benefits from the regulation of foreign commerce, which could enhance trade and economic opportunities for the state. This alignment with economic interests and a commitment to maintaining the institution of slavery distinguished South Carolina's decision from those of other states.