30 did the underground railroad work?

In the underground railroad, there were safe places that the slave hid and slept that were called "safe houses" or "stations". The slaves traveled in a couple set of routes with regular paths. The slaves hid and slept in stations during the day and then traveled at night, because the slaves owners were looking for them during the day, so the slaves would be safer if they hid and slept during the day.

Therefore the answer that you are looking for is,

All of the above.

I hope that this has satisfied you.

your answer would be (a)

the monroe doctrine is the best known u.s. policy toward the western hemisphere. buried in a routine annual message delivered to congress by president james monroe in december 1823, the doctrine warns european nations that the united states would not tolerate further colonization or puppet monarchs.