How does the underlined sentence contribute to the theme that culture can limit our thinking it indicates that the aunt's portrayal of right and wrong is inauthentic and unconvincing

I looks like you are already giving the answer. I will, however, provide the complete question and some explanation to add to what you posted.

Read the excerpt from "The Storyteller."

"She did all that she was told, she was always truthful, she kept her clothes clean, ate milk puddings as though they were jam tarts, learned her lessons perfectly, and was polite in her manners.” "Was she pretty?” asked the bigger of the small girls. "Not as pretty as any of you,” said the bachelor, "but she was horribly good.” There was a wave of reaction in favour of the story; the word horrible in connection with goodness was a novelty that commended itself. It seemed to introduce a ring of truth that was absent from the aunt’s tales of infant life.

How does the underlined sentence contribute to the theme that culture can limit our thinking?

It indicates that the aunt’s portrayal of right and wrong is inauthentic and unconvincing.

It shows that children and adults have opposing perspectives on what goodness is.

It characterizes the children as eager to accept any viewpoint that disagrees with their aunt’s.

It satirizes the bachelor’s conception of goodness by comparing it to

The correct option is A. It indicates that the aunt’s portrayal of right and wrong is inauthentic and unconvincing.

Explanation:

The most important part of the excerpt begins when the bachelor says the character of his story was "horribly good". Notice that the children listening to him appreciate how he phrased that quality. They feel the way the bachelors says it is more truthful and authentic. The children have just listened to a story told by their aunt. Her story was unconvincing, inauthentic. She portrayed goodness and appropriate behavior in an exaggerated manner, with the intention of teaching the children a lesson. She made her character be saved by others because she was good. The children immediately questioned such a moral, asking if the girl wouldn't have been saved had she not been good. The aunt is incapable of giving them a satisfactory explanation, only making them skeptical about her portrayal of right and wrong.