Final answer:
Slavery had been abolished, and workers had to be paid for their labor.
Step-by-step explanation:
The effect of Reconstruction that might have hurt the South's economy is option D: Slavery had been abolished, and workers had to be paid for their labor. During Reconstruction, the abolition of slavery meant that plantation owners had to pay their workers wages instead of relying on slave labor. This put a financial burden on the Southern economy, as plantation owners had to adjust to the new labor system and allocate funds for paying laborers.