Both "her" and "their" could be used correctly in this case, but i'm presuming they want you to write down "their" if it is a single choice question.
The nation achieved the goals that Frederick Douglass and Abraham Lincoln desired by eradicating slavery across all of America and ensuring that every black American are free and have equal participation in the society. The Constitution would be the backbone of this freedom.
I would say the answer would be C.
For wealth, money is usually green. In nature leaves and plants are many times green. Progress, the green light means go on a light for driving, usually meaning to go forward, like in studies and whatnot.
Hope this helps!
