Answer:
A.To establish the idea that the main characters were living in an ideal fairytale existence
Step-by-step explanation:
In Once Upon A Time by Nadine Gordimer, the purpose of the narrator beginning her story with the family living "happily ever after?" is to show that such was not realistic and also to use irony, even as it is shown in the title of the book.
The author began the book like this:
"In a house, in a suburb, in a city, there were a man and his wife who loved each other very much and were living happily ever after"
This shows that the main characters were living in an ideal fairytale existence.