The system of escape routes and hiding places for runaway slaves was known as Underground Railroads.
In the US, slavery led to the creation of such escape routes and safe houses in order to help slaves escape and lead a normal life after that. They would either run to Canada or free states within America which abolished slavery. One of the most famous leaders was Harriet Tubman.
Answer:
Your answer will be B. They asked the king to address their complaints.
1. gulf of tonkin incident
2. truman doctrine
3.containment of communism
probably a little off but it'll lead you in the right direction.
(I was literally learning this a couple months ago and my memory is a little rusty)