Why does the author choose to call the individuals who worked on the Underground Railroad "conductors"?

A They were responsible for driving the trains that took slaves from slavery in the South to freedom in the North.
B Even though it was not an actual railroad, the "conductors” were individuals responsible for helping slaves travel from the South to the North.
C They conducted trains and boats that took fugitive slaves back to their masters in the South.
D They carried pistols on their hips that were known by people in the North as "conductors."​