Answer:
Ottoman Turk rulers is the answer.
Explanation:
The Underground Railroad was the name of the escape routes used by slaves to escape the South and flee to the North. It was a network of special routes and safe houses that were used by both slaves and abolitionists who were sympathetic to their cause of escaping slavery. It started in the late 1700's and ended after the abolition of slavery. Canada was a popular destination, as slavery was prohibited their and had a longer border for easier access.
Triangular trade or triangle trade is a historical term indicating trade among three ports or regions. Triangular trade usually evolves when a region has export commodities that are not required in the region from which its major imports come. Triangular trade thus provides a method for rectifying trade imbalances between the above regions.