Answer: B. Industrialization spread in the south
Step-by-step explanation:
Operating spindles were a mark of industrialization in 1840 and from the map we see that New England had a lot of operating spindles which means that they were more industrial and less agrarian so option A is wrong.
Option B is most likely correct because you can see from the map that operating spindles are in smaller quantities in the South which could mean that they were only being introduced there at the time.
Option C cannot be inferred from the map.
The map show News England having more spindles than the South so the South is not richer than New England.