The best explanation for the causes of the Slave Code of 1740 is:
The Slave Code of 1740 was caused by a large-scale, deadly slave rebellion in South Carolina, and growing fears of future revolts.
The code was enacted in response to the Stono Rebellion of 1739, which was one of the largest slave uprisings in the British colonies. The rebellion and the subsequent fear of further uprisings led to stricter laws governing enslaved people in an effort to control the slave population and prevent future revolts.