Answer: The Wall
Step-by-step explanation:
In the frame story, the author Nadine Gordimer is asked to tell a childerns' story but she refuses to do that because of her artistic freedom so she decides to tell the story about one married couple.
That married couple was a wealthy one and they lived in a walled-off suburb. They had a son and they were afraid of ''people of another color''. They were afraid that they will come into their home. Because of that, they had installed the thing that later on killed their son and that was barbed wire.
- The symbol of the Wall- They built that wall on their own, together. With that wall, they have rejected freedom and they let fear in their life which was the thing that cost them.