Final answer:
The main source of income in South Carolina before the Civil War was agriculture, especially through the cultivation of cotton and tobacco.
Step-by-step explanation:
The primary way money was made in South Carolina prior to the Civil War was through agriculture. During the antebellum period, the southern states, including South Carolina, primarily focused on large agricultural plantations supported by slave labor. These plantations grew cotton for the mills of the North and tobacco for export. These agricultural products, particularly cotton, became the backbone of the southern economy, with the South producing the bulk of the world's supply of cotton during this time.