Which one does not belong steerage, emigrant, and suffrage?

Actually, emigrant is moving from one side of a country to another, not leaving a country. suffrage is the correct answer because it it’s the right to vote, which an example of is women’s suffrage.

Sufferage is the right to vote, steerage is the part of the ship that takes care of the lowest paying passengers, and emigrant is a person who leaves their own country (willingly) to permanently take residence in another. The one that doesn't fit would be sufferage.