Final answer:
The development of cash crops and the plantation system in the South was primarily caused by the availability of abundant land and favorable climate.
Step-by-step explanation:
The primary cause of the development of cash crops and the plantation system in the South was c) The availability of abundant land and favorable climate.
Plantation agriculture in the South became lucrative due to the presence of fertile land and a climate suitable for growing cash crops, such as cotton. The South had an abundance of land available for cultivation, and the warm climate provided optimal conditions for crops to thrive.
As a result, plantation owners in the South focused on growing cash crops for export, such as cotton, tobacco, and rice. These cash crops became highly profitable and contributed to the economic development of the region.