Based on the data on the charts, the most plausible inference about the states that show an increase in enslaved workers and have low cotton shares is:
Those states used slave labor to grow different crops.
This inference is supported by the observation that states like Alabama and North Carolina show a substantial increase in the number of enslaved workers, yet their cotton production share is either low or varies significantly. It suggests that these states may have been utilizing enslaved labor for other agricultural purposes rather than cotton production.