Question

why does gordimer incorporate the book of fairy tales as a symbol in once upon a time?
to reinforce the innocence of the young boy and show that good intentions can have bad outcomes
to create a parallel between the young boy and the narrator
to show that the young boy is no different than the children in the segregated quarter
to foreshadow the heroic qualities the boy shows at the end of the story

Explanation:

In "Once Upon a Time", the book of fairy - tales symbolizes innocence. The young boy's actions based on his innocent understanding from fairy - tales lead to bad outcomes, showing that good intentions can have negative results.

Answer:

to reinforce the innocence of the young boy and show that good intentions can have bad outcomes