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.
This code was implemented in response to the Stono Rebellion of 1739, which was a significant uprising of enslaved people in South Carolina that heightened fears of further insurrections, leading to stricter laws governing the behavior and rights of enslaved people.